UPBGE: Simplify texture blurring.

The shader used to blur a texture was using ftransform for gl_Position
and so it needed the modelview/prjection matrix to be set.
This can be avoided by using gl_Vertex directly.

source/blender/gpu/intern/gpu_framebuffer.c

@@ -523,21 +523,12 @@ void GPU_framebuffer_blur(
 
 	GPU_shader_bind(blur_shader);
 	GPU_shader_uniform_vector(blur_shader, scale_uniform, 2, 1, scaleh);
+	GPU_texture_bind(tex, 0);
 	GPU_shader_uniform_texture(blur_shader, texture_source_uniform, tex);
 	glViewport(0, 0, GPU_texture_width(blurtex), GPU_texture_height(blurtex));
 
-	/* Preparing to draw quad */
-	glMatrixMode(GL_TEXTURE);
-	glLoadIdentity();
-	glMatrixMode(GL_PROJECTION);
-	glLoadIdentity();
-	glMatrixMode(GL_MODELVIEW);
-	glLoadIdentity();
-
 	glDisable(GL_DEPTH_TEST);
 
-	GPU_texture_bind(tex, 0);
-
 	/* Drawing quad */
 	glBegin(GL_QUADS);
 	glTexCoord2d(0, 0); glVertex2f(1, 1);
@@ -553,10 +544,10 @@ void GPU_framebuffer_blur(
 
 	GG.currentfb = fb->object;
 
-	glViewport(0, 0, GPU_texture_width(tex), GPU_texture_height(tex));
 	GPU_shader_uniform_vector(blur_shader, scale_uniform, 2, 1, scalev);
-	GPU_shader_uniform_texture(blur_shader, texture_source_uniform, blurtex);
 	GPU_texture_bind(blurtex, 0);
+	GPU_shader_uniform_texture(blur_shader, texture_source_uniform, blurtex);
+	glViewport(0, 0, GPU_texture_width(tex), GPU_texture_height(tex));
 
 	glBegin(GL_QUADS);
 	glTexCoord2d(0, 0); glVertex2f(1, 1);
@@ -567,6 +558,8 @@ void GPU_framebuffer_blur(
 
 	GPU_texture_unbind(blurtex);
 	GPU_shader_unbind();
+
+	glEnable(GL_DEPTH_TEST);
 }
 
 /* GPURenderBuffer */

source/blender/gpu/shaders/gpu_shader_sep_gaussian_blur_vert.glsl

@@ -1,6 +1,5 @@
-
 void main()
 {
-	gl_Position = ftransform();
+	gl_Position = gl_Vertex;
 	gl_TexCoord[0] = gl_MultiTexCoord0;
 }