diff --git a/inc/opengl.h b/inc/opengl.h
index f3f19ba..4386059 100644
--- a/inc/opengl.h
+++ b/inc/opengl.h
@@ -8,6 +8,8 @@ BOOL OpenGL_ExtExists(char *ext);
 GLuint OpenGL_BuildProgram(const GLchar *vertSource, const GLchar *fragSource);
 GLuint OpenGL_BuildProgramFromFile(const char *filePath);
 
+typedef void (APIENTRYP PFNWGLSWAPINTERVALEXT) (int interval);
+
 // Program
 extern PFNGLCREATEPROGRAMPROC glCreateProgram;
 extern PFNGLDELETEPROGRAMPROC glDeleteProgram;
@@ -66,3 +68,5 @@ extern PFNGLFRAMEBUFFERTEXTURE2DPROC glFramebufferTexture2D;
 extern PFNGLDRAWBUFFERSPROC glDrawBuffers;
 extern PFNGLCHECKFRAMEBUFFERSTATUSPROC glCheckFramebufferStatus;
 extern PFNGLDELETEFRAMEBUFFERSPROC glDeleteFramebuffers;
+
+extern PFNWGLSWAPINTERVALEXT wglSwapIntervalEXT;
diff --git a/src/opengl.c b/src/opengl.c
index 1c60fdb..c7d5c67 100644
--- a/src/opengl.c
+++ b/src/opengl.c
@@ -62,6 +62,8 @@ PFNGLDRAWBUFFERSPROC glDrawBuffers = NULL;
 PFNGLCHECKFRAMEBUFFERSTATUSPROC glCheckFramebufferStatus = NULL;
 PFNGLDELETEFRAMEBUFFERSPROC glDeleteFramebuffers = NULL;
 
+PFNWGLSWAPINTERVALEXT wglSwapIntervalEXT = NULL;
+
 void OpenGL_Init()
 {
     // Program
@@ -120,6 +122,8 @@ void OpenGL_Init()
     glDrawBuffers = (PFNGLDRAWBUFFERSPROC)wglGetProcAddress("glDrawBuffers");
     glCheckFramebufferStatus = (PFNGLCHECKFRAMEBUFFERSTATUSPROC)wglGetProcAddress("glCheckFramebufferStatus");
     glDeleteFramebuffers = (PFNGLDELETEFRAMEBUFFERSPROC)wglGetProcAddress("glDeleteFramebuffers");
+
+    wglSwapIntervalEXT = (PFNWGLSWAPINTERVALEXT)wglGetProcAddress("wglSwapIntervalEXT");
 }
 
 BOOL OpenGL_ExtExists(char *ext)
diff --git a/src/render.c b/src/render.c
index f9ec6d0..c3eb1de 100644
--- a/src/render.c
+++ b/src/render.c
@@ -49,7 +49,6 @@ DWORD WINAPI render_main(void)
 
     if (OpenGL_ExtExists("WGL_EXT_swap_control"))
     {
-        BOOL(APIENTRY *wglSwapIntervalEXT)(int) = (BOOL(APIENTRY *)(int))wglGetProcAddress("wglSwapIntervalEXT");
         if (wglSwapIntervalEXT)
         {
             if (ddraw->vsync)
@@ -532,15 +531,19 @@ DWORD WINAPI render_main(void)
             }
         }
 
-        if (scaleProgram && paletteConvProgram)
+        if (paletteConvProgram)
         {
-            // draw surface into framebuffer
-            glUseProgram(paletteConvProgram);
-
             glActiveTexture(GL_TEXTURE0);
             glBindTexture(GL_TEXTURE_2D, surfaceTexId);
             glActiveTexture(GL_TEXTURE1);
             glBindTexture(GL_TEXTURE_2D, paletteTexId);
+            glActiveTexture(GL_TEXTURE0);
+        }
+
+        if (scaleProgram && paletteConvProgram)
+        {
+            // draw surface into framebuffer
+            glUseProgram(paletteConvProgram);
 
             glViewport(0, 0, ddraw->width, ddraw->height);