static uint16 Effect_GL_InitShader(int EffectIndex);
static uint16 GL_EffectShaderProgram[512];
static void GL_BindDefaultVertexArrays();
static void GL_InitTexture(gl_effect_layer *Test);

void Effect_GL_Levels(source *Source, layer_bitmap_info *BitmapInfo, memory *Memory, property_channel Property[])
{
    real32 All_Start = Property[0].CurrentValue.f;
    real32 All_Mid = Property[1].CurrentValue.f;
    real32 All_End = Property[2].CurrentValue.f;
    v4 Start = Property[3].CurrentValue.col;
    v4 Mid = Property[4].CurrentValue.col;
    v4 End = Property[5].CurrentValue.col;

    if (!BitmapInfo->Test.Initialized) {
        GL_InitTexture(&BitmapInfo->Test);
    }

    gl_effect_layer Test = BitmapInfo->Test;
    uint8 *Data = (uint8 *)BitmapInfo->BitmapBuffer;
    uint16 Width = Source->Info.Width;
    uint16 Height = Source->Info.Height;

    glBindTexture(GL_TEXTURE_2D, Test.Texture);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, Width, Height, 0, GL_RGBA,
                 GL_UNSIGNED_BYTE, Data);

    glBindFramebuffer(GL_FRAMEBUFFER, Test.FramebufferObject);
    glBindRenderbuffer(GL_RENDERBUFFER, Test.Color_Renderbuffer);

    uint16 ShaderProgram = Effect_GL_InitShader(1);

    GL_BindDefaultVertexArrays();

    int vertexColorLocation = glGetUniformLocation(ShaderProgram, "Start");
    glUniform1f(vertexColorLocation, All_Start);
    vertexColorLocation = glGetUniformLocation(ShaderProgram, "Mid");
    glUniform1f(vertexColorLocation, All_Mid);
    vertexColorLocation = glGetUniformLocation(ShaderProgram, "End");
    glUniform1f(vertexColorLocation, All_End);
    vertexColorLocation = glGetUniformLocation(ShaderProgram, "StartCol");
    glUniform4f(vertexColorLocation, Start.r, Start.g, Start.b,  Start.a);
    vertexColorLocation = glGetUniformLocation(ShaderProgram, "MidCol");
    glUniform4f(vertexColorLocation, Mid.r, Mid.g, Mid.b,  Mid.a);
    vertexColorLocation = glGetUniformLocation(ShaderProgram, "EndCol");
    glUniform4f(vertexColorLocation, End.r, End.g, End.b,  End.a);

    glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);

    glReadPixels(0, 0, Width, Height, GL_RGBA, GL_UNSIGNED_BYTE, &Data[0]);

    glBindFramebuffer(GL_FRAMEBUFFER, 0);

}

void Effect_GL_GaussianBlur(source *Source, layer_bitmap_info *BitmapInfo, memory *Memory, property_channel Property[])
{
    real32 Radius = Property[0].CurrentValue.f;

    if (!BitmapInfo->Test.Initialized) {
        GL_InitTexture(&BitmapInfo->Test);
    }

    gl_effect_layer Test = BitmapInfo->Test;
    uint8 *Data = (uint8 *)BitmapInfo->BitmapBuffer;
    uint16 Width = Source->Info.Width;
    uint16 Height = Source->Info.Height;

    glBindTexture(GL_TEXTURE_2D, Test.Texture);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, Width, Height, 0, GL_RGBA,
                 GL_UNSIGNED_BYTE, Data);

    glBindFramebuffer(GL_FRAMEBUFFER, Test.FramebufferObject);
    glBindRenderbuffer(GL_RENDERBUFFER, Test.Color_Renderbuffer);

    uint16 ShaderProgram = Effect_GL_InitShader(2);

    GL_BindDefaultVertexArrays();

    int vertexColorLocation = glGetUniformLocation(ShaderProgram, "Radius");
    glUniform1f(vertexColorLocation, Radius + 1.60f);
    vertexColorLocation = glGetUniformLocation(ShaderProgram, "Direction");
    glUniform2f(vertexColorLocation, 1.0f, 0.0f);

    glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
    glReadPixels(0, 0, Width, Height, GL_RGBA, GL_UNSIGNED_BYTE, &Data[0]);

    // This blur works in two passes.

    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, Width, Height, 0, GL_RGBA,
                 GL_UNSIGNED_BYTE, Data);

    vertexColorLocation = glGetUniformLocation(ShaderProgram, "Direction");
    glUniform2f(vertexColorLocation, 0.0f, 1.0f);

    glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
    glReadPixels(0, 0, Width, Height, GL_RGBA, GL_UNSIGNED_BYTE, &Data[0]);

    glBindFramebuffer(GL_FRAMEBUFFER, 0);

}