From 4b5c76eeee8950588dd89574e47ec32a6c8208b3 Mon Sep 17 00:00:00 2001
From: Sam Lantinga <slouken@libsdl.org>
Date: Wed, 9 Feb 2011 10:31:12 -0800
Subject: [PATCH] Fixed compiling on Windows Added an untested shader for YV12
 textures

---
 VisualC/SDL/SDL_VS2008.vcproj      |  8 +++++
 VisualC/SDL/SDL_VS2010.vcxproj     |  2 ++
 src/render/opengl/SDL_shaders_gl.c | 57 +++++++++++++++++++++++++++---
 src/render/opengl/SDL_shaders_gl.h |  2 +-
 4 files changed, 63 insertions(+), 6 deletions(-)
 mode change 100644 => 100755 src/render/opengl/SDL_shaders_gl.c

diff --git a/VisualC/SDL/SDL_VS2008.vcproj b/VisualC/SDL/SDL_VS2008.vcproj
index 98084683f..53fa5eedc 100644
--- a/VisualC/SDL/SDL_VS2008.vcproj
+++ b/VisualC/SDL/SDL_VS2008.vcproj
@@ -1054,6 +1054,14 @@
 			RelativePath="..\..\src\file\SDL_rwops.c"
 			>
 		</File>
+		<File
+			RelativePath="..\..\src\render\opengl\SDL_shaders_gl.c"
+			>
+		</File>
+		<File
+			RelativePath="..\..\src\render\opengl\SDL_shaders_gl.h"
+			>
+		</File>
 		<File
 			RelativePath="..\..\src\video\SDL_shape.c"
 			>
diff --git a/VisualC/SDL/SDL_VS2010.vcxproj b/VisualC/SDL/SDL_VS2010.vcxproj
index c964c4d5e..b180e9048 100644
--- a/VisualC/SDL/SDL_VS2010.vcxproj
+++ b/VisualC/SDL/SDL_VS2010.vcxproj
@@ -285,6 +285,7 @@ echo #define SDL_REVISION "hg-0:baadf00d" &gt;"$(ProjectDir)\..\..\include\SDL_r
     <ClInclude Include="..\..\src\libm\math.h" />
     <ClInclude Include="..\..\src\libm\math_private.h" />
     <ClInclude Include="..\..\src\render\mmx.h" />
+    <ClInclude Include="..\..\src\render\opengl\SDL_shaders_gl.h" />
     <ClInclude Include="..\..\src\render\SDL_sysrender.h" />
     <ClInclude Include="..\..\src\render\SDL_yuv_sw_c.h" />
     <ClInclude Include="..\..\src\audio\SDL_audio_c.h" />
@@ -373,6 +374,7 @@ echo #define SDL_REVISION "hg-0:baadf00d" &gt;"$(ProjectDir)\..\..\include\SDL_r
     <ClCompile Include="..\..\src\libm\s_sin.c" />
     <ClCompile Include="..\..\src\render\direct3d\SDL_render_d3d.c" />
     <ClCompile Include="..\..\src\render\opengl\SDL_render_gl.c" />
+    <ClCompile Include="..\..\src\render\opengl\SDL_shaders_gl.c" />
     <ClCompile Include="..\..\src\render\SDL_render.c" />
     <ClCompile Include="..\..\src\render\SDL_yuv_mmx.c" />
     <ClCompile Include="..\..\src\render\SDL_yuv_sw.c" />
diff --git a/src/render/opengl/SDL_shaders_gl.c b/src/render/opengl/SDL_shaders_gl.c
old mode 100644
new mode 100755
index 708b090ef..4fc569400
--- a/src/render/opengl/SDL_shaders_gl.c
+++ b/src/render/opengl/SDL_shaders_gl.c
@@ -112,6 +112,58 @@ static const char *shader_source[NUM_SHADERS][2] =
 "void main()\n"
 "{\n"
 "    gl_FragColor = texture2D(tex0, v_texCoord) * v_color;\n"
+"}"
+    },
+
+    /* SHADER_YV12 */
+    {
+        /* vertex shader */
+"varying vec4 v_color;\n"
+"varying vec2 v_texCoord;\n"
+"\n"
+"void main()\n"
+"{\n"
+"    gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;\n"
+"    v_color = gl_Color;\n"
+"    v_texCoord = vec2(gl_MultiTexCoord0);\n"
+"}",
+        /* fragment shader */
+"varying vec4 v_color;\n"
+"varying vec2 v_texCoord;\n"
+"uniform sampler2D tex0; // Y \n"
+"uniform sampler2D tex1; // U \n"
+"uniform sampler2D tex2; // V \n"
+"\n"
+"// YUV offset \n"
+"const vec3 offset = vec3(-0.0625, -0.5, -0.5);\n"
+"\n"
+"// RGB coefficients \n"
+"const vec3 Rcoeff = vec3(1.164,  0.000,  1.596);\n"
+"const vec3 Gcoeff = vec3(1.164, -0.391, -0.813);\n"
+"const vec3 Bcoeff = vec3(1.164,  2.018,  0.000);\n"
+"\n"
+"void main()\n"
+"{\n"
+"    vec2 tcoord;\n"
+"    vec3 yuv, rgb;\n"
+"\n"
+"    // Get the Y value \n"
+"    tcoord = v_texCoord;\n"
+"    yuv.x = texture2D(tex0, tcoord).r;\n"
+"\n"
+"    // Get the U and V values \n"
+"    tcoord *= 0.5;\n"
+"    yuv.y = texture2D(tex1, tcoord).r;\n"
+"    yuv.z = texture2D(tex2, tcoord).r;\n"
+"\n"
+"    // Do the color transform \n"
+"    yuv += offset;\n"
+"    rgb.r = dot(yuv, Rcoeff);\n"
+"    rgb.g = dot(yuv, Gcoeff);\n"
+"    rgb.b = dot(yuv, Bcoeff);\n"
+"\n"
+"    // That was easy. :) \n"
+"    gl_FragColor = vec4(rgb, 1.0) * v_color;\n"
 "}"
     },
 };
@@ -209,10 +261,6 @@ CompileShaderProgram(GL_ShaderContext *ctx, int index, GL_ShaderData *data)
 static void
 DestroyShaderProgram(GL_ShaderContext *ctx, GL_ShaderData *data)
 {
-    if (index == SHADER_NONE) {
-        return;
-    }
-
     ctx->glDeleteObjectARB(data->vert_shader);
     ctx->glDeleteObjectARB(data->frag_shader);
     ctx->glDeleteObjectARB(data->program);
@@ -281,7 +329,6 @@ GL_CreateShaderContext()
     /* Compile all the shaders */
     for (i = 0; i < NUM_SHADERS; ++i) {
         if (!CompileShaderProgram(ctx, i, &ctx->shaders[i])) {
-fprintf(stderr, "Unable to compile shader!\n");
             GL_DestroyShaderContext(ctx);
             return NULL;
         }
diff --git a/src/render/opengl/SDL_shaders_gl.h b/src/render/opengl/SDL_shaders_gl.h
index dfb821ba2..de2ed3d72 100644
--- a/src/render/opengl/SDL_shaders_gl.h
+++ b/src/render/opengl/SDL_shaders_gl.h
@@ -27,7 +27,7 @@ typedef enum {
     SHADER_NONE,
     SHADER_SOLID,
     SHADER_RGB,
-    //SHADER_YV12,
+    SHADER_YV12,
     NUM_SHADERS
 } GL_Shader;