From 0910c139eaafc66862deeb07056b56e1e4ed1c6b Mon Sep 17 00:00:00 2001
From: Gabriel Jacobo <gabomdq@gmail.com>
Date: Fri, 10 May 2013 10:31:01 -0300
Subject: [PATCH] Fixes OpenGL* Clip Rect functions (by Emmanuel Gil Peyrot)

---
 src/render/opengl/SDL_render_gl.c       |  2 +-
 src/render/opengles/SDL_glesfuncs.h     |  1 +
 src/render/opengles/SDL_render_gles.c   | 12 +++++++++---
 src/render/opengles2/SDL_gles2funcs.h   |  1 +
 src/render/opengles2/SDL_render_gles2.c | 12 +++++++++---
 5 files changed, 21 insertions(+), 7 deletions(-)

diff --git a/src/render/opengl/SDL_render_gl.c b/src/render/opengl/SDL_render_gl.c
index 08933fa2e..11c88d47c 100644
--- a/src/render/opengl/SDL_render_gl.c
+++ b/src/render/opengl/SDL_render_gl.c
@@ -794,7 +794,7 @@ GL_UpdateClipRect(SDL_Renderer * renderer)
 
     if (!SDL_RectEmpty(rect)) {
         data->glEnable(GL_SCISSOR_TEST);
-        data->glScissor(rect->x, rect->y, rect->x + rect->w, rect->y + rect->h);
+        data->glScissor(rect->x, rect->h - rect->y, rect->x, rect->y);
     } else {
         data->glDisable(GL_SCISSOR_TEST);
     }
diff --git a/src/render/opengles/SDL_glesfuncs.h b/src/render/opengles/SDL_glesfuncs.h
index aade01229..36f6fe7b6 100644
--- a/src/render/opengles/SDL_glesfuncs.h
+++ b/src/render/opengles/SDL_glesfuncs.h
@@ -20,6 +20,7 @@ SDL_PROC(void, glMatrixMode, (GLenum))
 SDL_PROC(void, glOrthof, (GLfloat, GLfloat, GLfloat, GLfloat, GLfloat, GLfloat))
 SDL_PROC(void, glPixelStorei, (GLenum, GLint))
 SDL_PROC(void, glReadPixels, (GLint, GLint, GLsizei, GLsizei, GLenum, GLenum, GLvoid*))
+SDL_PROC(void, glScissor, (GLint, GLint, GLsizei, GLsizei))
 SDL_PROC(void, glTexCoordPointer, (GLint, GLenum, GLsizei, const GLvoid *))
 SDL_PROC(void, glTexEnvf, (GLenum, GLenum, GLfloat))
 SDL_PROC(void, glTexImage2D, (GLenum, GLint, GLint, GLsizei, GLsizei, GLint, GLenum, GLenum, const GLvoid *))
diff --git a/src/render/opengles/SDL_render_gles.c b/src/render/opengles/SDL_render_gles.c
index 3a7a44152..a71a346d9 100644
--- a/src/render/opengles/SDL_render_gles.c
+++ b/src/render/opengles/SDL_render_gles.c
@@ -635,13 +635,19 @@ GLES_UpdateViewport(SDL_Renderer * renderer)
 static int
 GLES_UpdateClipRect(SDL_Renderer * renderer)
 {
+    GLES_RenderData *data = (GLES_RenderData *) renderer->driverdata;
     const SDL_Rect *rect = &renderer->clip_rect;
 
+    if (SDL_CurrentContext != data->context) {
+        /* We'll update the clip rect after we rebind the context */
+        return 0;
+    }
+
     if (!SDL_RectEmpty(rect)) {
-        glEnable(GL_SCISSOR_TEST);
-        glScissor(rect->x, rect->y, rect->x + rect->w, rect->y + rect->h);
+        data->glEnable(GL_SCISSOR_TEST);
+        data->glScissor(rect->x, rect->h - rect->y, rect->w, rect->h);
     } else {
-        glDisable(GL_SCISSOR_TEST);
+        data->glDisable(GL_SCISSOR_TEST);
     }
     return 0;
 }
diff --git a/src/render/opengles2/SDL_gles2funcs.h b/src/render/opengles2/SDL_gles2funcs.h
index 7b7d5e17d..d7cd1d515 100644
--- a/src/render/opengles2/SDL_gles2funcs.h
+++ b/src/render/opengles2/SDL_gles2funcs.h
@@ -30,6 +30,7 @@ SDL_PROC(GLint, glGetUniformLocation, (GLuint, const char *))
 SDL_PROC(void, glLinkProgram, (GLuint))
 SDL_PROC(void, glPixelStorei, (GLenum, GLint))
 SDL_PROC(void, glReadPixels, (GLint, GLint, GLsizei, GLsizei, GLenum, GLenum, GLvoid*))
+SDL_PROC(void, glScissor, (GLint, GLint, GLsizei, GLsizei))
 SDL_PROC(void, glShaderBinary, (GLsizei, const GLuint *, GLenum, const void *, GLsizei))
 SDL_PROC(void, glShaderSource, (GLuint, GLsizei, const char **, const GLint *))
 SDL_PROC(void, glTexImage2D, (GLenum, GLint, GLint, GLsizei, GLsizei, GLint, GLenum, GLenum, const void *))
diff --git a/src/render/opengles2/SDL_render_gles2.c b/src/render/opengles2/SDL_render_gles2.c
index f55283f69..3e3af7355 100644
--- a/src/render/opengles2/SDL_render_gles2.c
+++ b/src/render/opengles2/SDL_render_gles2.c
@@ -278,13 +278,19 @@ GLES2_UpdateViewport(SDL_Renderer * renderer)
 static int
 GLES2_UpdateClipRect(SDL_Renderer * renderer)
 {
+    GLES2_DriverContext *rdata = (GLES2_DriverContext *)renderer->driverdata;
     const SDL_Rect *rect = &renderer->clip_rect;
 
+    if (SDL_CurrentContext != rdata->context) {
+        /* We'll update the clip rect after we rebind the context */
+        return 0;
+    }
+
     if (!SDL_RectEmpty(rect)) {
-        glEnable(GL_SCISSOR_TEST);
-        glScissor(rect->x, rect->y, rect->x + rect->w, rect->y + rect->h);
+        rdata->glEnable(GL_SCISSOR_TEST);
+        rdata->glScissor(rect->x, rect->h - rect->y, rect->w, rect->h);
     } else {
-        glDisable(GL_SCISSOR_TEST);
+        rdata->glDisable(GL_SCISSOR_TEST);
     }
     return 0;
 }