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(Said Max Horn on the SDL mailing list...) Hi folks, based on Eric Wing's patch, I created the attached patch which fixes the OpenGL coordinate inversion bug in SDL. It works fine over here on 10.3 with Ryan's test program (which I also attached). There is another change in it: I removed the "- 1" in the two lines using CGDisplayPixelsHigh()... while I understand from a logical point of view why they *should* be correct, I checked the actual values computed that way, and they were off-by-one. After removing the " - 1", the returned mouse coordinates are correct. I checked this by moving the mouse to the screen top/bottom in fullscreen mode, BTW. With the change, the proper values 0 and 479 are returned (in 640x480 mode). Sam, you may still want to test on 10.1, it's very simple using Ryan's minimal test code :-) Cheers, Max (Here is the reproduction case for revision history's sake...) /* * To compile: * gcc -o test test.c `sdl-config --cflags` `sdl-config --libs` -framework OpenGL * * --ryan. */ #include <stdio.h> #include "SDL.h" #include "SDL_opengl.h" int main(int argc, char **argv) { Uint32 flags = SDL_OPENGL /* | SDL_FULLSCREEN */; SDL_Surface *screen; SDL_Event event; int done = 0; GLfloat ratio; SDL_Init(SDL_INIT_VIDEO); SDL_ShowCursor(0); if ((argv[1]) && (strcmp(argv[1], "--grab") == 0)) SDL_WM_GrabInput(SDL_GRAB_ON); screen = SDL_SetVideoMode(640, 480, 0, flags); if (!screen) return(42); ratio = ((GLfloat) screen->w) / ((GLfloat) screen->h); glClearColor( 0.0f, 0.0f, 0.0f, 0.0f ); glClearDepth( 1.0f ); glEnable( GL_DEPTH_TEST ); glDepthFunc( GL_LEQUAL ); glViewport( 0, 0, screen->w, screen->h); glMatrixMode( GL_PROJECTION ); glLoadIdentity(); gluPerspective( 45.0f, ratio, 0.1f, 100.0f ); glMatrixMode( GL_MODELVIEW ); glLoadIdentity(); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); SDL_GL_SwapBuffers(); // eh, close enough. #define MAX_X 6.12 #define MAX_Y 4.50 while (!done) { int x, y; GLfloat glx, gly; if (!SDL_WaitEvent(&event)) break; switch (event.type) { case SDL_KEYUP: if (event.key.keysym.sym == SDLK_ESCAPE) done = 1; break; } SDL_GetMouseState(&x, &y); glx = ((((GLfloat) x) / ((GLfloat) screen->w)) - 0.5f) * MAX_X; gly = ((((GLfloat) y) / ((GLfloat) screen->h)) - 0.5f) * MAX_Y; glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glLoadIdentity(); glTranslatef(glx,-gly,-6.0f); glBegin(GL_TRIANGLES); glColor3f(1,0,0); glVertex3f( 0.00f, 0.25f, 0.00f); glColor3f(0,1,0); glVertex3f(-0.25f, -0.25f, 0.00f); glColor3f(0,0,1); glVertex3f( 0.25f, -0.25f, 0.00f); glEnd(); SDL_GL_SwapBuffers(); } SDL_Quit(); return(0); } /* end of test.c ... */
author Ryan C. Gordon <icculus@icculus.org>
date Mon, 22 Mar 2004 09:38:20 +0000
parents 355632dca928
children
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>SDL_GL_SetAttribute</H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN2742"
></A
><H2
>Name</H2
>SDL_GL_SetAttribute&nbsp;--&nbsp;Set a special SDL/OpenGL attribute</DIV
><DIV
CLASS="REFSYNOPSISDIV"
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><H2
>Synopsis</H2
><DIV
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><P
></P
><PRE
CLASS="FUNCSYNOPSISINFO"
>#include "SDL.h"</PRE
><P
><CODE
><CODE
CLASS="FUNCDEF"
>int <B
CLASS="FSFUNC"
>SDL_GL_SetAttribute</B
></CODE
>(SDL_GLattr attr, int value);</CODE
></P
><P
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><DIV
CLASS="REFSECT1"
><A
NAME="AEN2752"
></A
><H2
>Description</H2
><P
>Sets the OpenGL <A
HREF="sdlglattr.html"
>attribute</A
> <TT
CLASS="PARAMETER"
><I
>attr</I
></TT
> to <TT
CLASS="PARAMETER"
><I
>value</I
></TT
>. The attributes you set don't take effect until after a call to <A
HREF="sdlsetvideomode.html"
><TT
CLASS="FUNCTION"
>SDL_SetVideoMode</TT
></A
>. You should use <A
HREF="sdlglgetattribute.html"
><TT
CLASS="FUNCTION"
>SDL_GL_GetAttribute</TT
></A
> to check the values after a <TT
CLASS="FUNCTION"
>SDL_SetVideoMode</TT
> call.</P
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>Return Value</H2
><P
>Returns <SPAN
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>0</SPAN
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CLASS="RETURNVALUE"
>-1</SPAN
> on error.</P
></DIV
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></A
><H2
>Example</H2
><PRE
CLASS="PROGRAMLISTING"
>SDL_GL_SetAttribute( SDL_GL_RED_SIZE, 5 );
SDL_GL_SetAttribute( SDL_GL_GREEN_SIZE, 5 );
SDL_GL_SetAttribute( SDL_GL_BLUE_SIZE, 5 );
SDL_GL_SetAttribute( SDL_GL_DEPTH_SIZE, 16 );
SDL_GL_SetAttribute( SDL_GL_DOUBLEBUFFER, 1 );
if ( (screen=SDL_SetVideoMode( 640, 480, 16, SDL_OPENGL )) == NULL ) {
  fprintf(stderr, "Couldn't set GL mode: %s\n", SDL_GetError());
  SDL_Quit();
  return;
}</PRE
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><B
>Note: </B
>The <TT
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>SDL_DOUBLEBUF</TT
> flag is not required to enable double buffering when setting an OpenGL video mode. Double buffering is enabled or disabled using the SDL_GL_DOUBLEBUFFER attribute.</P
></BLOCKQUOTE
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>See Also</H2
><P
><A
HREF="sdlglgetattribute.html"
><TT
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>SDL_GL_GetAttribute</TT
></A
>,
<A
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>GL Attributes</A
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