Fixed bug 1844 - glScissor calls are wrong - Patch attached

Martin Gerhardy the coordinate system from sdl is not correctly transformed to the coordinate system of opengl. glScissor expects them to be a little bit different. Attached is a patch that fixes this
libsdl-org · May 12, 2013 · 0f5d772 · 0f5d772
1 parent 5561d2e
commit 0f5d772
Show file tree

Hide file tree

Showing 3 changed files with 6 additions and 3 deletions.
diff --git a/src/render/opengl/SDL_render_gl.c b/src/render/opengl/SDL_render_gl.c
@@ -794,7 +794,8 @@ GL_UpdateClipRect(SDL_Renderer * renderer)
 
     if (!SDL_RectEmpty(rect)) {
         data->glEnable(GL_SCISSOR_TEST);
-        data->glScissor(rect->x, rect->h - rect->y, rect->w, rect->h);
+        int lowerLeft = renderer->viewport.h - rect->y - rect->h;
+        data->glScissor(rect->x, lowerLeft, rect->w, rect->h);
     } else {
         data->glDisable(GL_SCISSOR_TEST);
     }

diff --git a/src/render/opengles/SDL_render_gles.c b/src/render/opengles/SDL_render_gles.c
@@ -645,7 +645,8 @@ GLES_UpdateClipRect(SDL_Renderer * renderer)
 
     if (!SDL_RectEmpty(rect)) {
         data->glEnable(GL_SCISSOR_TEST);
-        data->glScissor(rect->x, rect->h - rect->y, rect->w, rect->h);
+        int lowerLeft = renderer->viewport.h - rect->y - rect->h;
+        data->glScissor(rect->x, lowerLeft, rect->w, rect->h);
     } else {
         data->glDisable(GL_SCISSOR_TEST);
     }

diff --git a/src/render/opengles2/SDL_render_gles2.c b/src/render/opengles2/SDL_render_gles2.c
@@ -288,7 +288,8 @@ GLES2_UpdateClipRect(SDL_Renderer * renderer)
 
     if (!SDL_RectEmpty(rect)) {
         rdata->glEnable(GL_SCISSOR_TEST);
-        rdata->glScissor(rect->x, rect->h - rect->y, rect->w, rect->h);
+        int lowerLeft = renderer->viewport.h - rect->y - rect->h;
+        rdata->glScissor(rect->x, lowerLeft, rect->w, rect->h);
     } else {
         rdata->glDisable(GL_SCISSOR_TEST);
     }