2382
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1 /*
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2 * fireworks.c
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3 * written by Holmes Futrell
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4 * use however you want
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5 */
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6
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7 #include "SDL.h"
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8 #include "math.h"
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9 #include "common.h"
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10 #include <math.h>
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11 #include <time.h>
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12 #include <OpenGLES/ES1/gl.h>
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13
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14 #define MILLESECONDS_PER_FRAME 16 /* about 60 frames per second */
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15 #define ACCEL 0.0001f
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16 #define WIND_RESISTANCE 0.00005f
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17 #define MAX_PARTICLES 2000
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18 #define VEL_BEFORE_EXPLODE 0.0f
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19
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20 SDL_TextureID flashTextureID;
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21
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22
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23 enum particleType {
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24 emitter = 0,
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25 trail,
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26 dust
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27 };
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28
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29 struct glformat {
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30 int SDL_GL_RED_SIZE;
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31 int SDL_GL_GREEN_SIZE;
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32 int SDL_GL_BLUE_SIZE;
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33 int SDL_GL_ALPHA_SIZE;
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34 int SDL_GL_BUFFER_SIZE;
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35 int SDL_GL_DOUBLEBUFFER;
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36 int SDL_GL_DEPTH_SIZE;
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37 int SDL_GL_STENCIL_SIZE;
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38 int SDL_GL_ACCUM_RED_SIZE;
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39 int SDL_GL_ACCUM_GREEN_SIZE;
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40 int SDL_GL_ACCUM_BLUE_SIZE;
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41 int SDL_GL_ACCUM_ALPHA_SIZE;
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42 int SDL_GL_STEREO;
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43 int SDL_GL_MULTISAMPLEBUFFERS;
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44 int SDL_GL_MULTISAMPLESAMPLES;
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45 int SDL_GL_ACCELERATED_VISUAL;
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46 int SDL_GL_RETAINED_BACKING;
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47 };
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48
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49 struct particle {
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50
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51 GLfloat x;
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52 GLfloat y;
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53 GLubyte color[4];
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54 GLfloat size;
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55 GLfloat xvel;
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56 GLfloat yvel;
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57 int isActive;
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58 enum particleType type;
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59 int framesSinceEmission;
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60 } particles[MAX_PARTICLES];
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61
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62 void spawnParticleFromEmitter(struct particle *emitter);
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63 void explodeEmitter(struct particle *emitter);
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64
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65 static int num_active_particles;
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66
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67 static void getError(const char *prefix)
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68 {
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69 const char *error;
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70
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71 GLenum result = glGetError();
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72 if (result == GL_NO_ERROR)
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73 return;
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74
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75 switch (result) {
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76 case GL_NO_ERROR:
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77 error = "GL_NO_ERROR";
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78 break;
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79 case GL_INVALID_ENUM:
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80 error = "GL_INVALID_ENUM";
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81 break;
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82 case GL_INVALID_VALUE:
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83 error = "GL_INVALID_VALUE";
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84 break;
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85 case GL_INVALID_OPERATION:
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86 error = "GL_INVALID_OPERATION";
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87 break;
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88 case GL_STACK_OVERFLOW:
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89 error = "GL_STACK_OVERFLOW";
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90 break;
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91 case GL_STACK_UNDERFLOW:
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92 error = "GL_STACK_UNDERFLOW";
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93 break;
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94 case GL_OUT_OF_MEMORY:
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95 error = "GL_OUT_OF_MEMORY";
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96 break;
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97 default:
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98 error = "UNKNOWN";
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99 break;
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100 }
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101 printf("%s: %s\n", prefix, error);
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102 }
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103
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104 void render(void) {
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105
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106 /* draw the background */
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107 glClear(GL_COLOR_BUFFER_BIT);
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108
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109 struct particle *slot = particles;
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110 struct particle *curr = particles;
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111 int i;
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112 for (i=0; i<num_active_particles; i++) {
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113 if (curr->isActive) {
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114
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115 if (curr->y > SCREEN_HEIGHT) curr->isActive = 0;
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116 if (curr->y < 0) curr->isActive = 0;
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117 if (curr->x > SCREEN_WIDTH) curr->isActive = 0;
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118 if (curr->x < 0) curr->isActive = 0;
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119
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120 curr->yvel += ACCEL * MILLESECONDS_PER_FRAME;
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121 curr->xvel += 0.0f;
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122 curr->y += curr->yvel * MILLESECONDS_PER_FRAME;
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123 curr->x += curr->xvel * MILLESECONDS_PER_FRAME;
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124
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125 if (curr->type == emitter) {
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126 spawnParticleFromEmitter(curr);
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127 curr->framesSinceEmission = 0;
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128 if (curr->yvel > -VEL_BEFORE_EXPLODE) {
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129 explodeEmitter(curr);
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130 }
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131 curr->framesSinceEmission++;
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132 }
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133 else {
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134
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135 float speed = sqrt(curr->xvel*curr->xvel + curr->yvel*curr->yvel);
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136
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137 if (WIND_RESISTANCE * MILLESECONDS_PER_FRAME < speed) {
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138 float normx = curr->xvel / speed;
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139 float normy = curr->yvel / speed;
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140 curr->xvel -= normx * WIND_RESISTANCE * MILLESECONDS_PER_FRAME;
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141 curr->yvel -= normy * WIND_RESISTANCE * MILLESECONDS_PER_FRAME;
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142 }
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143 else {
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144 curr->xvel = 0;
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145 curr->yvel = 0;
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146 }
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147
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148 if (curr->color[3] <= MILLESECONDS_PER_FRAME * 0.0005f * 255) {
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149 curr->isActive = 0;
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150
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151 }
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152 else {
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153 curr->color[3] -= MILLESECONDS_PER_FRAME * 0.0005f * 255;
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154 }
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155
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156 if (curr->type == dust)
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157 curr->size -= MILLESECONDS_PER_FRAME * 0.010f;
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158
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159 }
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160
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161 *(slot++) = *curr;
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162 }
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163 curr++;
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164 }
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165 num_active_particles = slot - particles;
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166
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167 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
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168 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
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169 glTexEnvi(GL_POINT_SPRITE_OES, GL_COORD_REPLACE_OES, 1);
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170
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171 glEnableClientState(GL_VERTEX_ARRAY);
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172 glVertexPointer(2, GL_FLOAT, sizeof(struct particle), particles + 0);
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173 getError("vertices");
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174
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175 glEnableClientState(GL_COLOR_ARRAY);
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176 glColorPointer(4, GL_UNSIGNED_BYTE, sizeof(struct particle), particles[0].color);
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177 getError("colors");
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178
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179 glEnableClientState(GL_POINT_SIZE_ARRAY_OES);
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180 getError("enable client state");
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181 glPointSizePointerOES(GL_FLOAT, sizeof(struct particle), &(particles[0].size));
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182 getError("point size");
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183
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184 glEnable(GL_POINT_SPRITE_OES);
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185 glDrawArrays(GL_POINTS, 0, num_active_particles);
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186 getError("glDrawArrays");
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187
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188
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189 /* update screen */
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190 SDL_RenderPresent();
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191
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192 }
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193
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194 void printOpenGLAttributes(struct glformat *format) {
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195 printf("\tSDL_GL_RED_SIZE = %d\n", format->SDL_GL_RED_SIZE);
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196 printf("\tSDL_GL_GREEN_SIZE = %d\n", format->SDL_GL_GREEN_SIZE);
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197 printf("\tSDL_GL_BLUE_SIZE = %d\n", format->SDL_GL_BLUE_SIZE);
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198 printf("\tSDL_GL_ALPHA_SIZE = %d\n", format->SDL_GL_ALPHA_SIZE);
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199 printf("\tSDL_GL_BUFFER_SIZE = %d\n", format->SDL_GL_BUFFER_SIZE);
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200 printf("\tSDL_GL_DOUBLEBUFFER = %d\n", format->SDL_GL_DOUBLEBUFFER);
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201 printf("\tSDL_GL_DEPTH_SIZE = %d\n", format->SDL_GL_DEPTH_SIZE);
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202 printf("\tSDL_GL_STENCIL_SIZE = %d\n", format->SDL_GL_STENCIL_SIZE);
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203 printf("\tSDL_GL_ACCUM_RED_SIZE = %d\n", format->SDL_GL_ACCUM_RED_SIZE);
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204 printf("\tSDL_GL_ACCUM_GREEN_SIZE = %d\n", format->SDL_GL_ACCUM_GREEN_SIZE);
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205 printf("\tSDL_GL_ACCUM_BLUE_SIZE = %d\n", format->SDL_GL_ACCUM_BLUE_SIZE);
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206 printf("\tSDL_GL_ACCUM_ALPHA_SIZE = %d\n", format->SDL_GL_ACCUM_ALPHA_SIZE);
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207 printf("\tSDL_GL_STEREO = %d\n", format->SDL_GL_STEREO);
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208 printf("\tSDL_GL_MULTISAMPLEBUFFERS = %d\n", format->SDL_GL_MULTISAMPLEBUFFERS);
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209 printf("\tSDL_GL_MULTISAMPLESAMPLES = %d\n", format->SDL_GL_MULTISAMPLESAMPLES);
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210 printf("\tSDL_GL_ACCELERATED_VISUAL = %d\n", format->SDL_GL_ACCELERATED_VISUAL);
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211 printf("\tSDL_GL_RETAINED_BACKING = %d\n", format->SDL_GL_RETAINED_BACKING);
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212 }
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213
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214 void setOpenGLAttributes(struct glformat *format) {
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215 SDL_GL_SetAttribute(SDL_GL_RED_SIZE, format->SDL_GL_RED_SIZE);
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216 SDL_GL_SetAttribute(SDL_GL_GREEN_SIZE, format->SDL_GL_GREEN_SIZE);
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217 SDL_GL_SetAttribute(SDL_GL_BLUE_SIZE, format->SDL_GL_BLUE_SIZE);
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218 SDL_GL_SetAttribute(SDL_GL_ALPHA_SIZE, format->SDL_GL_ALPHA_SIZE);
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219 SDL_GL_SetAttribute(SDL_GL_BUFFER_SIZE, format->SDL_GL_BUFFER_SIZE);
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220 SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, format->SDL_GL_DOUBLEBUFFER);
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221 SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, format->SDL_GL_DEPTH_SIZE);
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222 SDL_GL_SetAttribute(SDL_GL_STENCIL_SIZE, format->SDL_GL_STENCIL_SIZE);
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223 SDL_GL_SetAttribute(SDL_GL_ACCUM_RED_SIZE, format->SDL_GL_ACCUM_RED_SIZE);
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224 SDL_GL_SetAttribute(SDL_GL_ACCUM_GREEN_SIZE, format->SDL_GL_ACCUM_GREEN_SIZE);
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225 SDL_GL_SetAttribute(SDL_GL_ACCUM_BLUE_SIZE, format->SDL_GL_ACCUM_BLUE_SIZE);
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226 SDL_GL_SetAttribute(SDL_GL_ACCUM_ALPHA_SIZE, format->SDL_GL_ACCUM_ALPHA_SIZE);
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227 SDL_GL_SetAttribute(SDL_GL_STEREO, format->SDL_GL_STEREO);
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228 SDL_GL_SetAttribute(SDL_GL_MULTISAMPLEBUFFERS, format->SDL_GL_MULTISAMPLEBUFFERS);
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229 SDL_GL_SetAttribute(SDL_GL_MULTISAMPLESAMPLES, format->SDL_GL_MULTISAMPLESAMPLES);
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230 SDL_GL_SetAttribute(SDL_GL_ACCELERATED_VISUAL, format->SDL_GL_ACCELERATED_VISUAL);
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231 SDL_GL_SetAttribute(SDL_GL_RETAINED_BACKING, format->SDL_GL_RETAINED_BACKING);
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232 }
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233
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234 void getOpenGLAttributes(struct glformat *format) {
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235
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236 SDL_GL_GetAttribute(SDL_GL_RED_SIZE, &(format->SDL_GL_RED_SIZE));
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237 SDL_GL_GetAttribute(SDL_GL_GREEN_SIZE, &(format->SDL_GL_GREEN_SIZE));
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238 SDL_GL_GetAttribute(SDL_GL_BLUE_SIZE, &(format->SDL_GL_BLUE_SIZE));
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239 SDL_GL_GetAttribute(SDL_GL_ALPHA_SIZE, &(format->SDL_GL_ALPHA_SIZE));
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240 SDL_GL_GetAttribute(SDL_GL_BUFFER_SIZE, &(format->SDL_GL_BUFFER_SIZE));
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241 SDL_GL_GetAttribute(SDL_GL_DOUBLEBUFFER, &(format->SDL_GL_DOUBLEBUFFER));
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242 SDL_GL_GetAttribute(SDL_GL_DEPTH_SIZE, &(format->SDL_GL_DEPTH_SIZE));
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243 SDL_GL_GetAttribute(SDL_GL_STENCIL_SIZE, &(format->SDL_GL_STENCIL_SIZE));
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244 SDL_GL_GetAttribute(SDL_GL_ACCUM_RED_SIZE, &(format->SDL_GL_ACCUM_RED_SIZE));
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245 SDL_GL_GetAttribute(SDL_GL_ACCUM_GREEN_SIZE, &(format->SDL_GL_ACCUM_GREEN_SIZE));
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246 SDL_GL_GetAttribute(SDL_GL_ACCUM_BLUE_SIZE, &(format->SDL_GL_ACCUM_BLUE_SIZE));
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247 SDL_GL_GetAttribute(SDL_GL_ACCUM_ALPHA_SIZE, &(format->SDL_GL_ACCUM_ALPHA_SIZE));
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248 SDL_GL_GetAttribute(SDL_GL_STEREO, &(format->SDL_GL_STEREO));
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249 SDL_GL_GetAttribute(SDL_GL_MULTISAMPLEBUFFERS, &(format->SDL_GL_MULTISAMPLEBUFFERS));
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250 SDL_GL_GetAttribute(SDL_GL_MULTISAMPLESAMPLES, &(format->SDL_GL_MULTISAMPLESAMPLES));
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251 SDL_GL_GetAttribute(SDL_GL_ACCELERATED_VISUAL, &(format->SDL_GL_ACCELERATED_VISUAL));
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252 SDL_GL_GetAttribute(SDL_GL_RETAINED_BACKING, &(format->SDL_GL_RETAINED_BACKING));
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253 }
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254
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255 void explodeEmitter(struct particle *emitter) {
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256
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257 emitter->isActive = 0;
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258
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259 int i;
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260 for (i=0; i<200; i++) {
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261
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262 if (num_active_particles >= MAX_PARTICLES) return;
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263
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264 float theta = randomFloat(0, 2.0f * 3.141592);
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265 float max = 3.0f;
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266 float speed = randomFloat(0.00, powf(0.17, max));
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267 speed = powf(speed, 1.0f / max);
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268
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269 struct particle *p = &particles[num_active_particles];
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270 p->xvel = speed * cos(theta);
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271 p->yvel = speed * sin(theta);
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272 p->x = emitter->x + emitter->xvel;
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273 p->y = emitter->y + emitter->yvel;
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274 p->isActive = 1;
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275 p->type = dust;
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276 p->color[0] = emitter->color[0];
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277 p->color[1] = emitter->color[1];
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278 p->color[2] = emitter->color[2];
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279 p->color[3] = 255;
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280
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281 p->size = 15;
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282
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283 num_active_particles++;
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284
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285 }
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286
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287 }
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288
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289 void spawnParticleFromEmitter(struct particle *emitter) {
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290
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291 if (num_active_particles >= MAX_PARTICLES) return;
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292
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293 struct particle *p = &particles[num_active_particles];
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294 p->x = emitter->x + randomFloat(-3.0, 3.0);
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295 p->y = emitter->y + emitter->size / 2.0f;
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296 p->xvel = emitter->xvel + randomFloat(-0.005, 0.005);
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297 p->yvel = emitter->yvel + 0.1;
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298 p->color[0] = (0.8f + randomFloat(-0.1, 0.0)) * 255;
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299 p->color[1] = (0.4f + randomFloat(-0.1, 0.1)) * 255;
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300 p->color[2] = (0.0f + randomFloat(0.0, 0.2)) * 255;
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301 p->color[3] = (0.7f) * 255;
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302 p->size = 10;
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303 p->type = trail;
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304 p->isActive = 1;
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305 num_active_particles++;
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306
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307 }
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308
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309 void spawnEmitterParticle(int x, int y) {
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310
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311 if (num_active_particles >= MAX_PARTICLES) return;
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312
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313 struct particle *p = &particles[num_active_particles];
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314 p->x = x;
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315 p->y = SCREEN_HEIGHT;
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316 p->xvel = 0;
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317 p->yvel = -sqrt(2*ACCEL*(SCREEN_HEIGHT-y) + VEL_BEFORE_EXPLODE * VEL_BEFORE_EXPLODE);
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318 p->color[0] = 1.0 * 255;
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319 p->color[1] = 0.4 * 255;
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320 p->color[2] = 0.4 * 255;
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321 p->color[3] = 1.0f * 255;
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322 p->size = 10;
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323 p->type = emitter;
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324 p->framesSinceEmission = 0;
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325 p->isActive = 1;
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326 num_active_particles++;
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327 }
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328
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329 void initializeParticles(void) {
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330
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331 num_active_particles = 0;
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332
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333 }
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334
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335 /*
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336 loads the brush texture
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337 */
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338 void initializeTexture() {
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339 SDL_Surface *bmp_surface;
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340 bmp_surface = SDL_LoadBMP("stroke.bmp");
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341 if (bmp_surface == NULL) {
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342 fatalError("could not load stroke.bmp");
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343 }
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344 flashTextureID = SDL_CreateTextureFromSurface(SDL_PIXELFORMAT_ABGR8888, bmp_surface);
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345 SDL_FreeSurface(bmp_surface);
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346 if (flashTextureID == 0) {
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347 fatalError("could not create brush texture");
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348 }
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349 glEnable(GL_TEXTURE_2D);
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350 glEnable(GL_BLEND);
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351 glBlendFunc(GL_SRC_ALPHA, GL_ONE);
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352 }
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353
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354 int main(int argc, char *argv[]) {
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355
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356 SDL_WindowID windowID; /* ID of main window */
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357 Uint32 startFrame; /* time frame began to process */
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358 Uint32 endFrame; /* time frame ended processing */
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359 Uint32 delay; /* time to pause waiting to draw next frame */
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360 int done; /* should we clean up and exit? */
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361
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362 struct glformat requested, obtained;
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363
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364 /* initialize SDL */
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365 if (SDL_Init(SDL_INIT_VIDEO) < 0) {
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366 fatalError("Could not initialize SDL");
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367 }
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368
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369 srand(time(NULL));
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370
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371 SDL_GL_LoadLibrary(NULL);
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372
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373 SDL_memset(&requested, 0, sizeof(requested));
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374 requested.SDL_GL_RED_SIZE = 5;
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375 requested.SDL_GL_GREEN_SIZE = 6;
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376 requested.SDL_GL_BLUE_SIZE = 5;
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377 requested.SDL_GL_ALPHA_SIZE = 0;
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378 requested.SDL_GL_DEPTH_SIZE = 0;
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379 requested.SDL_GL_RETAINED_BACKING = 0;
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380 requested.SDL_GL_ACCELERATED_VISUAL = 1;
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381
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382 setOpenGLAttributes(&requested);
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383
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384 /* create main window and renderer */
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385 windowID = SDL_CreateWindow(NULL, 0, 0, SCREEN_WIDTH, SCREEN_HEIGHT,\
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386 SDL_WINDOW_OPENGL|SDL_WINDOW_SHOWN|SDL_WINDOW_BORDERLESS);
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387 SDL_CreateRenderer(windowID, 0, 0);
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388
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389 printf("Requested:\n");
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390 printOpenGLAttributes(&requested);
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391
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392 printf("obtained:\n");
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393 getOpenGLAttributes(&obtained);
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394 printOpenGLAttributes(&obtained);
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395
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396 initializeTexture();
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397
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398 done = 0;
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399 /* enter main loop */
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400 while(!done) {
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401 startFrame = SDL_GetTicks();
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402 SDL_Event event;
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403 while (SDL_PollEvent(&event)) {
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404 if (event.type == SDL_QUIT) {
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405 done = 1;
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406 }
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407 if (event.type == SDL_MOUSEBUTTONDOWN) {
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408 printf("mouse down\n");
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409 int which = event.button.which;
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410 int x, y;
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411 SDL_SelectMouse(which);
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412 SDL_GetMouseState(&x, &y);
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413 spawnEmitterParticle(x, y);
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414 }
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415 }
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416 render();
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417 endFrame = SDL_GetTicks();
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418
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419 /* figure out how much time we have left, and then sleep */
|
|
420 delay = MILLESECONDS_PER_FRAME - (endFrame - startFrame);
|
|
421 if (delay > MILLESECONDS_PER_FRAME) {
|
|
422 delay = MILLESECONDS_PER_FRAME;
|
|
423 }
|
|
424 if (delay > 0) {
|
|
425 SDL_Delay(delay);
|
|
426 }
|
|
427
|
|
428 //SDL_Delay(delay);
|
|
429 }
|
|
430
|
|
431 /* delete textures */
|
|
432
|
|
433 /* shutdown SDL */
|
|
434 SDL_Quit();
|
|
435
|
|
436 return 0;
|
|
437
|
|
438 } |