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view README.DirectFB @ 3333:b334b4f7dfa0
[SDL] Bad math in SDL_RenderCopy
Mason Wheeler to sdl
When I tried to render an image using something other than NULL for srcrect, it got horribly distorted. I traced it down to the fact that the math in the rectangle adjustments performed just before the call to renderer->RenderCopy is written inside out. It should look like this:
if (dstrect->w != real_dstrect.w) {
int deltax = (dstrect->x - real_dstrect.x);
int deltaw = (dstrect->w - real_dstrect.w);
real_srcrect.x += (deltax * real_srcrect.w) / dstrect->w;
real_srcrect.w += (deltaw * real_srcrect.w) / dstrect->w;
}
if (dstrect->h != real_dstrect.h) {
int deltay = (dstrect->y - real_dstrect.y);
int deltah = (dstrect->h - real_dstrect.h);
real_srcrect.y += (deltay * real_srcrect.h) / dstrect->h;
real_srcrect.h += (deltah * real_srcrect.h) / dstrect->h;
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Sat, 03 Oct 2009 16:23:16 +0000 |
parents | d72a0dd80e8b |
children | b196d2758026 |
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SDL on DirectFB Supports: - Hardware YUV overlays - OpenGL - software only - 2D/3D accelerations (depends on directfb driver) - multiple displays - windows What you need: DirectFB 1.0.1, 1.2.x, 1.3.0 Kernel-Framebuffer support: required: vesafb, radeonfb .... Mesa 7.0.x - optional for OpenGL /etc/directfbrc This file should contain the following lines to make your joystick work and avoid crashes: ------------------------ disable-module=joystick disable-module=cle266 disable-module=cyber5k no-linux-input-grab ------------------------ To disable to use x11 backend when DISPLAY variable is found use export SDL_DIRECTFB_X11_CHECK=0 To disable the use of linux input devices, i.e. multimice/multikeyboard support, use export SDL_DIRECTFB_LINUX_INPUT=0 To use hardware accelerated YUV-overlays for YUV-textures, use: export SDL_DIRECTFB_YUV_DIRECT=1 This is disabled by default. It will only support one YUV texture, namely the first. Every other YUV texture will be rendered in software. In addition, you may use (directfb-1.2.x) export SDL_DIRECTFB_YUV_UNDERLAY=1 to make the YUV texture an underlay. This will make the cursor to be shown. Simple Window Manager ===================== The driver has support for a very, very basic window manager you may want to use when runnning with "wm=default". Use export SDL_DIRECTFB_WM=1 to enable basic window borders. In order to have the window title rendered, you need to have the following font installed: /usr/share/fonts/truetype/freefont/FreeSans.ttf OPENGL Support ============== As of this writing 20070810 you need to pull Mesa from git and do the following: ------------------------ cd mesa make linux-directfb make echo Installing - please enter sudo pw. sudo make install INSTALL_DIR=/usr/local/dfb_GL cd src/mesa/drivers/directfb make sudo make install INSTALL_DIR=/usr/local/dfb_GL ------------------------ To run the SDL - testprograms: export SDL_VIDEODRIVER=directfb export LD_LIBRARY_PATH=/usr/local/dfb_GL/lib export LD_PRELOAD=/usr/local/dfb_GL/libGL.so.7 ./testgl