Merge lp:~timfelgentreff/stratagus/shaders into lp:stratagus

[timfelgentreff]

Adds shaders that are used with OpenGL to scale the entire screen. For now, the 'ctrl+alt+/' (backslash) key is globally bound to cycle through available shaders so you can try it.

[lp:~timfelgentreff/stratagus/shaders]

9032. By timfelgentreff on 2015-10-19

add scale2x (aka advmame2x) as scaling shader

9033. By timfelgentreff on 2015-10-19

add cmdline switches for shaders, add ctrl+alt+/ as hard cycle keybinding, remove debug prints

[timfelgentreff (timfelgentreff)]

Ok, I've made a few cleanups, there is now a global key-combo to cycle through shaders (ctrl+alt+/) and the shaders can also be selected from the cmdline. If anyone has time to test this, that would be great. Otherwise, I'll just merge this in a couple of days

=== modified file 'CMakeLists.txt'
--- CMakeLists.txt	2015-04-12 09:55:12 +0000
+++ CMakeLists.txt	2015-10-19 16:16:43 +0000
@@ -348,6 +348,7 @@
 	src/video/movie.cpp
 	src/video/png.cpp
 	src/video/sdl.cpp
+	src/video/shaders.cpp
 	src/video/sprite.cpp
 	src/video/video.cpp
 )
@@ -554,6 +555,7 @@
 	src/include/script.h
 	src/include/script_sound.h
 	src/include/settings.h
+	src/include/shaders.h
 	src/include/sound.h
 	src/include/sound_server.h
 	src/include/spells.h
@@ -932,7 +934,14 @@
 
 if(ENABLE_MULTIBUILD)
     if(WIN32 AND MSVC)
-      set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /MP")
+      if(MSVC_VERSION GREATER 1800)       # if > VC13 
+        message("The project must be compiled with VS2013 or older. VS2015 has deprecated many functions that we still use.") 
+        set(CMAKE_GENERATOR_TOOLSET "v120" CACHE STRING "Platform Toolset" FORCE) 
+		set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} /SAFESEH:NO /NODEFAULTLIB:MSVCRT")
+        set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} /SAFESEH:NO /NODEFAULTLIB:MSVCRT")
+        set(CMAKE_MODULE_LINKER_FLAGS "${CMAKE_MODULE_LINKER_FLAGS} /SAFESEH:NO /NODEFAULTLIB:MSVCRT")
+      endif()
+	  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /MP")
       message(STATUS "Added parallel build arguments to CMAKE_CXX_FLAGS: ${CMAKE_CXX_FLAGS}")
     endif()
 endif()

=== added file 'src/include/shaders.h'
--- src/include/shaders.h	1970-01-01 00:00:00 +0000
+++ src/include/shaders.h	2015-10-19 16:16:43 +0000
@@ -0,0 +1,11 @@
+#ifndef __SHADERS_H__
+#define __SHADERS_H__
+#ifdef USE_OPENGL
+#define MAX_SHADERS 5
+extern unsigned ShaderIndex;
+extern void LoadShaders();
+extern bool LoadShaderExtensions();
+extern void SetupFramebuffer();
+extern void RenderFramebufferToScreen();
+#endif
+#endif

=== modified file 'src/include/video.h'
--- src/include/video.h	2015-03-11 19:07:07 +0000
+++ src/include/video.h	2015-10-19 16:16:43 +0000
@@ -41,6 +41,7 @@
 
 #ifdef USE_OPENGL
 #include "SDL_opengl.h"
+#include "shaders.h"
 #endif
 
 #include "guichan.h"

=== modified file 'src/stratagus/stratagus.cpp'
--- src/stratagus/stratagus.cpp	2015-04-12 09:54:50 +0000
+++ src/stratagus/stratagus.cpp	2015-10-19 16:16:43 +0000
@@ -477,6 +477,9 @@
 		"\t-v mode\t\tVideo mode resolution in format <xres>x<yres>\n"
 		"\t-W\t\tWindowed video mode\n"
 #if defined(USE_OPENGL) || defined(USE_GLES)
+		"\t-x\t\tControls fullscreen scaling if your graphics card supports shaders.\n"\
+		"\t  \t\tPass 1 for nearest-neigubour, 2 for EPX/AdvMame, 3 for HQx, 4 for SAL, 5 for SuperEagle\n"\
+		"\t  \t\tYou can also use Ctrl+Alt+/ to cycle between these scaling algorithms at runtime.\n"
 		"\t-Z\t\tUse OpenGL to scale the screen to the viewport (retro-style). Implies -O.\n"
 #endif
 		"map is relative to StratagusLibPath=datapath, use ./map for relative to cwd\n",
@@ -529,7 +532,7 @@
 void ParseCommandLine(int argc, char **argv, Parameters &parameters)
 {
 	for (;;) {
-		switch (getopt(argc, argv, "ac:d:D:eE:FhiI:lN:oOP:ps:S:u:v:WZ?")) {
+		switch (getopt(argc, argv, "ac:d:D:eE:FhiI:lN:oOP:ps:S:u:v:Wx:Z?")) {
 			case 'a':
 				EnableAssert = true;
 				continue;
@@ -629,6 +632,9 @@
 				Video.FullScreen = 0;
 				continue;
 #if defined(USE_OPENGL) || defined(USE_GLES)
+			case 'x':
+				ShaderIndex = atoi(optarg) % MAX_SHADERS;
+				continue;
 			case 'Z':
 				ForceUseOpenGL = 1;
 				UseOpenGL = 1;

=== modified file 'src/video/sdl.cpp'
--- src/video/sdl.cpp	2015-03-05 17:12:52 +0000
+++ src/video/sdl.cpp	2015-10-19 16:16:43 +0000
@@ -70,6 +70,7 @@
 
 #ifdef USE_OPENGL
 #include "SDL_opengl.h"
+#include "shaders.h"
 #endif
 
 #ifdef USE_BEOS
@@ -122,6 +123,7 @@
 GLint GLMaxTextureSizeOverride;     /// User-specified limit for ::GLMaxTextureSize
 bool GLTextureCompressionSupported; /// Is OpenGL texture compression supported
 bool UseGLTextureCompression;       /// Use OpenGL texture compression
+bool GLShaderPipelineSupported;
 #endif
 
 static std::map<int, std::string> Key2Str;
@@ -256,8 +258,11 @@
 	} else {
 		GLTextureCompressionSupported = false;
 	}
+
+	GLShaderPipelineSupported = LoadShaderExtensions();
 #else
 	GLTextureCompressionSupported = false;
+	GLShaderPipelineSupported = false;
 #endif
 }
 
@@ -281,7 +286,11 @@
 #endif
 
 #ifdef USE_OPENGL
-	glOrtho(0, Video.Width, Video.Height, 0, -1, 1);
+	if (!GLShaderPipelineSupported) {
+		glOrtho(0, Video.Width, Video.Height, 0, -1, 1);
+	} else {
+		glOrtho(0, Video.ViewportWidth, Video.ViewportHeight, 0, -1, 1);
+	}
 #endif
 
 	glMatrixMode(GL_MODELVIEW);
@@ -299,6 +308,10 @@
 
 #ifdef USE_OPENGL
 	glClearDepth(1.0f);
+
+	if (GLShaderPipelineSupported) {
+		SetupFramebuffer();
+	}
 #endif
 
 	glShadeModel(GL_FLAT);
@@ -879,6 +892,13 @@
 			break;
 
 		case SDL_KEYDOWN:
+			if (GLShaderPipelineSupported
+				&& event.key.keysym.sym == SDLK_SLASH
+				&& event.key.keysym.mod & KMOD_ALT
+				&& event.key.keysym.mod & KMOD_CTRL) {
+				LoadShaders();
+				break;
+			}
 			InputKeyButtonPress(callbacks, SDL_GetTicks(),
 								event.key.keysym.sym, event.key.keysym.unicode);
 			break;
@@ -999,7 +1019,11 @@
 		eglSwapBuffers(eglDisplay, eglSurface);
 #endif
 #if defined(USE_OPENGL) || defined(USE_GLES_NATIVE)
-		SDL_GL_SwapBuffers();
+		if (GLShaderPipelineSupported) {
+			RenderFramebufferToScreen();
+		} else {
+			SDL_GL_SwapBuffers();
+		}
 #endif
 		glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 	} else

=== added file 'src/video/shaders.cpp'
--- src/video/shaders.cpp	1970-01-01 00:00:00 +0000
+++ src/video/shaders.cpp	2015-10-19 16:16:43 +0000
@@ -0,0 +1,502 @@
+#include "stratagus.h"
+#include "video.h"
+#ifdef USE_OPENGL
+const char* vertex_shader = "#version 130\n\
+\n\
+uniform sampler2D u_texture;\n\
+\n\
+void main()\n\
+{\n\
+    gl_TexCoord[0] = gl_MultiTexCoord0;\n\
+	gl_Position = ftransform();\n\
+}";
+
+const char* fragment_shaders[MAX_SHADERS] = {
+	// Nearest-neighbour
+	"#version 130\n\
+	\n\
+	uniform sampler2D u_texture;\n\
+	uniform float u_width;\n\
+	uniform float u_height;\n\
+	uniform float u_widthrel;\n\
+	uniform float u_heightrel;\n\
+	void main()\n\
+	{\n\
+		vec4 myColor = texture2D(u_texture, gl_TexCoord[0].xy * vec2(u_widthrel, -u_heightrel));\n\
+		gl_FragColor = myColor;\n\
+	}",
+	// Scale2x
+	"#version 110\n\
+	\n\
+	uniform sampler2D u_texture;\n\
+	uniform float u_width;\n\
+	uniform float u_height;\n\
+	uniform float u_widthrel;\n\
+	uniform float u_heightrel;\n\
+	\n\
+	void main() {\n\
+		// o = offset, the width of a pixel\n\
+        vec2 texCoord = gl_TexCoord[0].xy * vec2(u_widthrel, -u_heightrel);\n\
+        vec2 textureDimensions = vec2(u_width, u_height);\n\
+		vec2 o = 1.0 / textureDimensions;\n\
+		// texel arrangement\n\
+		// A B C\n\
+		// D E F\n\
+		// G H I\n\
+		vec4 A = texture2D(u_texture, texCoord + vec2( -o.x,  o.y));\n\
+		vec4 B = texture2D(u_texture, texCoord + vec2(    0,  o.y));\n\
+		vec4 C = texture2D(u_texture, texCoord + vec2(  o.x,  o.y));\n\
+		vec4 D = texture2D(u_texture, texCoord + vec2( -o.x,    0));\n\
+		vec4 E = texture2D(u_texture, texCoord + vec2(    0,    0));\n\
+		vec4 F = texture2D(u_texture, texCoord + vec2(  o.x,    0));\n\
+		vec4 G = texture2D(u_texture, texCoord + vec2( -o.x, -o.y));\n\
+		vec4 H = texture2D(u_texture, texCoord + vec2(    0, -o.y));\n\
+		vec4 I = texture2D(u_texture, texCoord + vec2(  o.x, -o.y));\n\
+		vec2 p = texCoord * textureDimensions;\n\
+		// p = the position within a pixel [0...1]\n\
+		p = p - floor(p);\n\
+		if (p.x > .5) {\n\
+			if (p.y > .5) {\n\
+				// Top Right\n\
+				gl_FragColor = B == F && B != D && F != H ? F : E;\n\
+			} else {\n\
+				// Bottom Right\n\
+				gl_FragColor = H == F && D != H && B != F ? F : E;\n\
+			}\n\
+		} else {\n\
+			if (p.y > .5) {\n\
+				// Top Left\n\
+				gl_FragColor = D == B && B != F && D != H ? D : E;\n\
+			} else {\n\
+				// Bottom Left\n\
+				gl_FragColor = D == H && D != B && H != F ? D : E;\n\
+			}\n\
+		}\n\
+	}",
+	// HQX
+	"#version 130\n\
+	\n\
+	uniform sampler2D u_texture;\n\
+	uniform float u_width;\n\
+	uniform float u_height;\n\
+	uniform float u_widthrel;\n\
+	uniform float u_heightrel;\n\
+	\n\
+	const float mx = 0.325;      // start smoothing wt.\n\
+	const float k = -0.250;      // wt. decrease factor\n\
+	const float max_w = 0.25;    // max filter weigth\n\
+	const float min_w =-0.05;    // min filter weigth\n\
+	const float lum_add = 0.25;  // effects smoothing \n\
+	\n\
+	void main()\n\
+	{\n\
+	   vec2 v_texCoord = gl_TexCoord[0].xy * vec2(u_widthrel, -u_heightrel);\n\
+	\n\
+	   // hq2x\n\
+	   float x = 0.5 * (1.0 / u_width);\n\
+	   float y = 0.5 * (1.0 / u_height);\n\
+	   vec2 dg1 = vec2( x, y);\n\
+	   vec2 dg2 = vec2(-x, y);\n\
+	   vec2 dx = vec2(x, 0.0);\n\
+	   vec2 dy = vec2(0.0, y);\n\
+	\n\
+	   vec4 TexCoord[5];\n\
+	   TexCoord[0] = vec4(v_texCoord, 0.0, 0.0);\n\
+	   TexCoord[1].xy = TexCoord[0].xy - dg1;\n\
+	   TexCoord[1].zw = TexCoord[0].xy - dy;\n\
+	   TexCoord[2].xy = TexCoord[0].xy - dg2;\n\
+	   TexCoord[2].zw = TexCoord[0].xy + dx;\n\
+	   TexCoord[3].xy = TexCoord[0].xy + dg1;\n\
+	   TexCoord[3].zw = TexCoord[0].xy + dy;\n\
+	   TexCoord[4].xy = TexCoord[0].xy + dg2;\n\
+	   TexCoord[4].zw = TexCoord[0].xy - dx;\n\
+	\n\
+	   vec3 c00 = texture2D(u_texture, TexCoord[1].xy).xyz; \n\
+	   vec3 c10 = texture2D(u_texture, TexCoord[1].zw).xyz; \n\
+	   vec3 c20 = texture2D(u_texture, TexCoord[2].xy).xyz; \n\
+	   vec3 c01 = texture2D(u_texture, TexCoord[4].zw).xyz; \n\
+	   vec3 c11 = texture2D(u_texture, TexCoord[0].xy).xyz; \n\
+	   vec3 c21 = texture2D(u_texture, TexCoord[2].zw).xyz; \n\
+	   vec3 c02 = texture2D(u_texture, TexCoord[4].xy).xyz; \n\
+	   vec3 c12 = texture2D(u_texture, TexCoord[3].zw).xyz; \n\
+	   vec3 c22 = texture2D(u_texture, TexCoord[3].xy).xyz; \n\
+	   vec3 dt = vec3(1.0, 1.0, 1.0);\n\
+	\n\
+	   float md1 = dot(abs(c00 - c22), dt);\n\
+	   float md2 = dot(abs(c02 - c20), dt);\n\
+	\n\
+	   float w1 = dot(abs(c22 - c11), dt) * md2;\n\
+	   float w2 = dot(abs(c02 - c11), dt) * md1;\n\
+	   float w3 = dot(abs(c00 - c11), dt) * md2;\n\
+	   float w4 = dot(abs(c20 - c11), dt) * md1;\n\
+	\n\
+	   float t1 = w1 + w3;\n\
+	   float t2 = w2 + w4;\n\
+	   float ww = max(t1, t2) + 0.0001;\n\
+	\n\
+	   c11 = (w1 * c00 + w2 * c20 + w3 * c22 + w4 * c02 + ww * c11) / (t1 + t2 + ww);\n\
+	\n\
+	   float lc1 = k / (0.12 * dot(c10 + c12 + c11, dt) + lum_add);\n\
+	   float lc2 = k / (0.12 * dot(c01 + c21 + c11, dt) + lum_add);\n\
+	\n\
+	   w1 = clamp(lc1 * dot(abs(c11 - c10), dt) + mx, min_w, max_w);\n\
+	   w2 = clamp(lc2 * dot(abs(c11 - c21), dt) + mx, min_w, max_w);\n\
+	   w3 = clamp(lc1 * dot(abs(c11 - c12), dt) + mx, min_w, max_w);\n\
+	   w4 = clamp(lc2 * dot(abs(c11 - c01), dt) + mx, min_w, max_w);\n\
+	   \n\
+	   gl_FragColor = vec4(w1 * c10 + w2 * c21 + w3 * c12 + w4 * c01 + (1.0 - w1 - w2 - w3 - w4) * c11, 1);\n\
+	}",
+	// 2xSAL
+	"#version 130\n\
+	\n\
+	uniform sampler2D u_texture;\n\
+	uniform float u_width;\n\
+	uniform float u_height;\n\
+	uniform float u_widthrel;\n\
+	uniform float u_heightrel;\n\
+	\n\
+	void main()\n\
+	{\n\
+	   vec2 texCoord = gl_TexCoord[0].xy * vec2(u_widthrel, -u_heightrel);\n\
+	   vec2 UL, UR, DL, DR;\n\
+	   float dx = pow(u_width, -1.0) * 0.25;\n\
+	   float dy = pow(u_height, -1.0) * 0.25;\n\
+	   vec3 dt = vec3(1.0, 1.0, 1.0);\n\
+	   UL = texCoord + vec2(-dx, -dy);\n\
+	   UR = texCoord + vec2(dx, -dy);\n\
+	   DL = texCoord + vec2(-dx, dy);\n\
+	   DR = texCoord + vec2(dx, dy);\n\
+	   vec3 c00 = texture2D(u_texture, UL).xyz;\n\
+	   vec3 c20 = texture2D(u_texture, UR).xyz;\n\
+	   vec3 c02 = texture2D(u_texture, DL).xyz;\n\
+	   vec3 c22 = texture2D(u_texture, DR).xyz;\n\
+	   float m1=dot(abs(c00-c22),dt)+0.001;\n\
+	   float m2=dot(abs(c02-c20),dt)+0.001;\n\
+	   gl_FragColor = vec4((m1*(c02+c20)+m2*(c22+c00))/(2.0*(m1+m2)),1.0); \n\
+	}",
+	// SuperEagle
+	"#version 130\n\
+	\n\
+	uniform sampler2D u_texture;\n\
+	uniform float u_width;\n\
+	uniform float u_height;\n\
+	uniform float u_widthrel;\n\
+	uniform float u_heightrel;\n\
+	\n\
+	int GET_RESULT(float A, float B, float C, float D)\n\
+	{\n\
+		int x = 0; int y = 0; int r = 0;\n\
+		if (A == C) x+=1; else if (B == C) y+=1;\n\
+		if (A == D) x+=1; else if (B == D) y+=1;\n\
+		if (x <= 1) r+=1; \n\
+		if (y <= 1) r-=1;\n\
+		return r;\n\
+	} \n\
+	\n\
+	const vec3 dtt = vec3(65536.0,255.0,1.0);\n\
+	\n\
+	float reduce(vec3 color)\n\
+	{ \n\
+		return dot(color, dtt);\n\
+	}\n\
+	\n\
+	void main()\n\
+	{\n\
+	   // get texel size   	\n\
+		vec2 ps = vec2(0.999/u_width, 0.999/u_height);\n\
+	\n\
+		vec2 v_texCoord = gl_TexCoord[0].xy * vec2(u_widthrel, -u_heightrel);\n\
+	\n\
+		// calculating offsets, coordinates\n\
+		vec2 dx = vec2( ps.x, 0.0); \n\
+		vec2 dy = vec2( 0.0, ps.y);\n\
+		vec2 g1 = vec2( ps.x,ps.y);\n\
+		vec2 g2 = vec2(-ps.x,ps.y);	\n\
+		\n\
+		vec2 pixcoord  = v_texCoord/ps;	//VAR.CT\n\
+		vec2 fp        = fract(pixcoord);\n\
+		vec2 pC4       = v_texCoord-fp*ps;\n\
+		vec2 pC8       = pC4+g1;		//VAR.CT\n\
+	\n\
+		// Reading the texels\n\
+		vec3 C0 = texture2D(u_texture,pC4-g1).xyz; \n\
+		vec3 C1 = texture2D(u_texture,pC4-dy).xyz;\n\
+		vec3 C2 = texture2D(u_texture,pC4-g2).xyz;\n\
+		vec3 D3 = texture2D(u_texture,pC4-g2+dx).xyz;\n\
+		vec3 C3 = texture2D(u_texture,pC4-dx).xyz;\n\
+		vec3 C4 = texture2D(u_texture,pC4   ).xyz;\n\
+		vec3 C5 = texture2D(u_texture,pC4+dx).xyz;\n\
+		vec3 D4 = texture2D(u_texture,pC8-g2).xyz;\n\
+		vec3 C6 = texture2D(u_texture,pC4+g2).xyz;\n\
+		vec3 C7 = texture2D(u_texture,pC4+dy).xyz;\n\
+		vec3 C8 = texture2D(u_texture,pC4+g1).xyz;\n\
+		vec3 D5 = texture2D(u_texture,pC8+dx).xyz;\n\
+		vec3 D0 = texture2D(u_texture,pC4+g2+dy).xyz;\n\
+		vec3 D1 = texture2D(u_texture,pC8+g2).xyz;\n\
+		vec3 D2 = texture2D(u_texture,pC8+dy).xyz;\n\
+		vec3 D6 = texture2D(u_texture,pC8+g1).xyz;\n\
+	\n\
+		vec3 p00,p10,p01,p11;\n\
+	\n\
+		// reducing vec3 to float	\n\
+		float c0 = reduce(C0);float c1 = reduce(C1);\n\
+		float c2 = reduce(C2);float c3 = reduce(C3);\n\
+		float c4 = reduce(C4);float c5 = reduce(C5);\n\
+		float c6 = reduce(C6);float c7 = reduce(C7);\n\
+		float c8 = reduce(C8);float d0 = reduce(D0);\n\
+		float d1 = reduce(D1);float d2 = reduce(D2);\n\
+		float d3 = reduce(D3);float d4 = reduce(D4);\n\
+		float d5 = reduce(D5);float d6 = reduce(D6);\n\
+	\n\
+		/*              SuperEagle code               */\n\
+		/*  Copied from the Dosbox source code        */\n\
+		/*  Copyright (C) 2002-2007  The DOSBox Team  */\n\
+		/*  License: GNU-GPL                          */\n\
+		/*  Adapted by guest(r) on 16.4.2007          */       \n\
+		if (c4 != c8) {\n\
+			if (c7 == c5) {\n\
+				p01 = p10 = C7;\n\
+				if ((c6 == c7) || (c5 == c2)) {\n\
+						p00 = 0.25*(3.0*C7+C4);\n\
+				} else {\n\
+						p00 = 0.5*(C4+C5);\n\
+				}\n\
+	\n\
+				if ((c5 == d4) || (c7 == d1)) {\n\
+						p11 = 0.25*(3.0*C7+C8);\n\
+				} else {\n\
+						p11 = 0.5*(C7+C8);\n\
+				}\n\
+			} else {\n\
+				p11 = 0.125*(6.0*C8+C7+C5);\n\
+				p00 = 0.125*(6.0*C4+C7+C5);\n\
+	\n\
+				p10 = 0.125*(6.0*C7+C4+C8);\n\
+				p01 = 0.125*(6.0*C5+C4+C8);\n\
+			}\n\
+		} else {\n\
+			if (c7 != c5) {\n\
+				p11 = p00 = C4;\n\
+	\n\
+				if ((c1 == c4) || (c8 == d5)) {\n\
+						p01 = 0.25*(3.0*C4+C5);\n\
+				} else {\n\
+						p01 = 0.5*(C4+C5);\n\
+				}\n\
+	\n\
+				if ((c8 == d2) || (c3 == c4)) {\n\
+						p10 = 0.25*(3.0*C4+C7);\n\
+				} else {\n\
+						p10 = 0.5*(C7+C8);\n\
+				}\n\
+			} else {\n\
+				int r = 0;\n\
+				r += GET_RESULT(c5,c4,c6,d1);\n\
+				r += GET_RESULT(c5,c4,c3,c1);\n\
+				r += GET_RESULT(c5,c4,d2,d5);\n\
+				r += GET_RESULT(c5,c4,c2,d4);\n\
+	\n\
+				if (r > 0) {\n\
+						p01 = p10 = C7;\n\
+						p00 = p11 = 0.5*(C4+C5);\n\
+				} else if (r < 0) {\n\
+						p11 = p00 = C4;\n\
+						p01 = p10 = 0.5*(C4+C5);\n\
+				} else {\n\
+						p11 = p00 = C4;\n\
+						p01 = p10 = C7;\n\
+				}\n\
+			}\n\
+		}\n\
+	\n\
+		// Distributing the four products	\n\
+		if (fp.x < 0.50)\n\
+			{ if (fp.y < 0.50) p10 = p00;}\n\
+		else\n\
+			{ if (fp.y < 0.50) p10 = p01; else p10 = p11;}\n\
+	\n\
+		gl_FragColor = vec4(p10, 1);\n\
+	}"
+};
+
+
+PFNGLCREATESHADERPROC glCreateShader;
+PFNGLSHADERSOURCEPROC glShaderSource;
+PFNGLCOMPILESHADERPROC glCompileShader;
+PFNGLCREATEPROGRAMPROC glCreateProgram;
+PFNGLATTACHSHADERPROC glAttachShader;
+PFNGLLINKPROGRAMPROC glLinkProgram;
+PFNGLUSEPROGRAMPROC glUseProgram;
+PFNGLISPROGRAMPROC glIsProgram;
+PFNGLDELETEPROGRAMPROC glDeleteProgram;
+PFNGLDELETESHADERPROC glDeleteShader;
+PFNGLGETSHADERIVPROC glGetShaderiv;
+PFNGLGETPROGRAMIVPROC glGetProgramiv;
+PFNGLGETSHADERINFOLOGPROC glGetShaderInfoLog;
+PFNGLGETPROGRAMINFOLOGPROC glGetProgramInfoLog;
+PFNGLGETUNIFORMLOCATIONPROC glGetUniformLocation;
+PFNGLACTIVETEXTUREPROC glActiveTexture;
+PFNGLUNIFORM1FPROC glUniform1f;
+PFNGLUNIFORM1IPROC glUniform1i;
+
+GLuint fullscreenShader;
+GLuint fullscreenFramebuffer = 0;
+GLuint fullscreenTexture;
+PFNGLGENFRAMEBUFFERSEXTPROC glGenFramebuffers;
+PFNGLBINDFRAMEBUFFEREXTPROC glBindFramebuffer;
+PFNGLFRAMEBUFFERTEXTURE2DEXTPROC glFramebufferTexture;
+PFNGLGENRENDERBUFFERSEXTPROC glGenRenderbuffers;
+PFNGLBINDRENDERBUFFEREXTPROC glBindRenderbuffer;
+PFNGLRENDERBUFFERSTORAGEEXTPROC glRenderbufferStorage;
+PFNGLFRAMEBUFFERRENDERBUFFEREXTPROC glFramebufferRenderbuffer;
+PFNGLDRAWBUFFERSPROC glDrawBuffers;
+PFNGLCHECKFRAMEBUFFERSTATUSEXTPROC glCheckFramebufferStatus;
+
+void printShaderInfoLog(GLuint obj, const char* prefix)
+{
+	int infologLength = 0;
+	int charsWritten = 0;
+	char *infoLog;
+
+	glGetShaderiv(obj, GL_INFO_LOG_LENGTH, &infologLength);
+
+	if (infologLength > 0)
+	{
+		infoLog = (char *)malloc(infologLength);
+		glGetShaderInfoLog(obj, infologLength, &charsWritten, infoLog);
+		fprintf(stdout, "%s: %s\n", prefix, infoLog);
+		free(infoLog);
+	}
+}
+void printProgramInfoLog(GLuint obj, const char* prefix)
+{
+	int infologLength = 0;
+	int charsWritten = 0;
+	char *infoLog;
+
+	glGetProgramiv(obj, GL_INFO_LOG_LENGTH, &infologLength);
+
+	if (infologLength > 0)
+	{
+		infoLog = (char *)malloc(infologLength);
+		glGetProgramInfoLog(obj, infologLength, &charsWritten, infoLog);
+		fprintf(stdout, "%s: %s\n", prefix, infoLog);
+		free(infoLog);
+	}
+}
+
+extern unsigned ShaderIndex = 0;
+
+extern void LoadShaders() {
+	GLuint vs, fs;
+	fs = glCreateShader(GL_FRAGMENT_SHADER);
+	glShaderSource(fs, 1, (const char**)&(fragment_shaders[ShaderIndex]), NULL);
+	glCompileShader(fs);
+	//printShaderInfoLog(fs, "Fragment Shader");
+	ShaderIndex = (ShaderIndex + 1) % MAX_SHADERS;
+	vs = glCreateShader(GL_VERTEX_SHADER);
+	glShaderSource(vs, 1, (const char**)&vertex_shader, NULL);
+	glCompileShader(vs);
+	//printShaderInfoLog(vs, "Vertex Shader");
+	if (glIsProgram(fullscreenShader)) {
+		glDeleteProgram(fullscreenShader);
+	}
+	fullscreenShader = glCreateProgram();
+	glAttachShader(fullscreenShader, vs);
+	glAttachShader(fullscreenShader, fs);
+	glLinkProgram(fullscreenShader);
+	glDeleteShader(fs);
+	glDeleteShader(vs);
+	//printProgramInfoLog(fullscreenShader, "Shader Program");
+}
+
+extern bool LoadShaderExtensions() {
+	glCreateShader = (PFNGLCREATESHADERPROC)(uintptr_t)SDL_GL_GetProcAddress("glCreateShader");
+	glShaderSource = (PFNGLSHADERSOURCEPROC)(uintptr_t)SDL_GL_GetProcAddress("glShaderSource");
+	glCompileShader = (PFNGLCOMPILESHADERPROC)(uintptr_t)SDL_GL_GetProcAddress("glCompileShader");
+	glCreateProgram = (PFNGLCREATEPROGRAMPROC)(uintptr_t)SDL_GL_GetProcAddress("glCreateProgram");
+	glAttachShader = (PFNGLATTACHSHADERPROC)(uintptr_t)SDL_GL_GetProcAddress("glAttachShader");
+	glLinkProgram = (PFNGLLINKPROGRAMPROC)(uintptr_t)SDL_GL_GetProcAddress("glLinkProgram");
+	glUseProgram = (PFNGLUSEPROGRAMPROC)(uintptr_t)SDL_GL_GetProcAddress("glUseProgram");
+	glGetShaderiv = (PFNGLGETSHADERIVPROC)(uintptr_t)SDL_GL_GetProcAddress("glGetShaderiv");
+	glGetProgramiv = (PFNGLGETPROGRAMIVPROC)(uintptr_t)SDL_GL_GetProcAddress("glGetProgramiv");
+	glGetShaderInfoLog = (PFNGLGETSHADERINFOLOGPROC)(uintptr_t)SDL_GL_GetProcAddress("glGetShaderInfoLog");
+	glGetProgramInfoLog = (PFNGLGETPROGRAMINFOLOGPROC)(uintptr_t)SDL_GL_GetProcAddress("glGetProgramInfoLog");
+	glIsProgram = (PFNGLISPROGRAMPROC)(uintptr_t)SDL_GL_GetProcAddress("glIsProgram");
+	glDeleteProgram = (PFNGLDELETEPROGRAMPROC)(uintptr_t)SDL_GL_GetProcAddress("glDeleteProgram");
+	glDeleteShader = (PFNGLDELETESHADERPROC)(uintptr_t)SDL_GL_GetProcAddress("glDeleteShader");
+
+	glGetUniformLocation = (PFNGLGETUNIFORMLOCATIONPROC)(uintptr_t)SDL_GL_GetProcAddress("glGetUniformLocation");
+	glActiveTexture = (PFNGLACTIVETEXTUREPROC)(uintptr_t)SDL_GL_GetProcAddress("glActiveTexture");
+	glUniform1f = (PFNGLUNIFORM1FPROC)(uintptr_t)SDL_GL_GetProcAddress("glUniform1f");
+	glUniform1i = (PFNGLUNIFORM1IPROC)(uintptr_t)SDL_GL_GetProcAddress("glUniform1i");
+
+	glGenFramebuffers = (PFNGLGENFRAMEBUFFERSEXTPROC)(uintptr_t)SDL_GL_GetProcAddress("glGenFramebuffers");
+	glBindFramebuffer = (PFNGLBINDFRAMEBUFFEREXTPROC)(uintptr_t)SDL_GL_GetProcAddress("glBindFramebuffer");
+	glFramebufferTexture = (PFNGLFRAMEBUFFERTEXTURE2DEXTPROC)(uintptr_t)SDL_GL_GetProcAddress("glFramebufferTexture2D");
+	glGenRenderbuffers = (PFNGLGENRENDERBUFFERSEXTPROC)(uintptr_t)SDL_GL_GetProcAddress("glGenRenderbuffers");
+	glBindRenderbuffer = (PFNGLBINDRENDERBUFFEREXTPROC)(uintptr_t)SDL_GL_GetProcAddress("glBindRenderbuffer");
+	glRenderbufferStorage = (PFNGLRENDERBUFFERSTORAGEEXTPROC)(uintptr_t)SDL_GL_GetProcAddress("glRenderbufferStorage");
+	glFramebufferRenderbuffer = (PFNGLFRAMEBUFFERRENDERBUFFEREXTPROC)(uintptr_t)SDL_GL_GetProcAddress("glFramebufferRenderbuffer");
+	glDrawBuffers = (PFNGLDRAWBUFFERSPROC)(uintptr_t)SDL_GL_GetProcAddress("glDrawBuffers");
+	glCheckFramebufferStatus = (PFNGLCHECKFRAMEBUFFERSTATUSEXTPROC)(uintptr_t)SDL_GL_GetProcAddress("glCheckFramebufferStatus");
+
+	if (glCreateShader && glGenFramebuffers && glGetUniformLocation && glActiveTexture) {
+		LoadShaders();
+		return true;
+	} else {
+		return false;
+	}
+}
+
+extern void SetupFramebuffer() {
+	glGenTextures(1, &fullscreenTexture); // generate a texture to render to off-screen
+	glBindTexture(GL_TEXTURE_2D, fullscreenTexture); // bind it, so all texture functions go to it
+	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, Video.ViewportWidth, Video.ViewportHeight, 0, GL_RGBA, GL_UNSIGNED_BYTE, 0); // give an empty image to opengl
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST); // make sure we use nearest filtering
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+	glGenFramebuffers(1, &fullscreenFramebuffer); // generate a framebuffer to render to
+	glBindFramebuffer(GL_FRAMEBUFFER_EXT, fullscreenFramebuffer); // bind it
+	glFramebufferTexture(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_2D, fullscreenTexture, 0); // set our texture as the "screen" of the framebuffer
+	GLenum DrawBuffers[1] = { GL_COLOR_ATTACHMENT0_EXT };
+	glDrawBuffers(1, DrawBuffers);
+	if (glCheckFramebufferStatus(GL_FRAMEBUFFER_EXT) != GL_FRAMEBUFFER_COMPLETE_EXT) {
+		fprintf(stderr, "FATAL: Error Creating Framebuffer! Try running without OpenGL.");
+		exit(-1);
+	}
+	glBindFramebuffer(GL_FRAMEBUFFER_EXT, fullscreenFramebuffer);
+}
+
+extern void RenderFramebufferToScreen() {
+	// switch the rendering target back to the real display
+	glBindFramebuffer(GL_FRAMEBUFFER_EXT, 0);
+	// setup our shader program
+	glUseProgram(fullscreenShader);
+	GLint textureloc = glGetUniformLocation(fullscreenShader, "u_texture");
+	GLint widthloc = glGetUniformLocation(fullscreenShader, "u_width");
+	GLint heightloc = glGetUniformLocation(fullscreenShader, "u_height");
+	GLint widthrelloc = glGetUniformLocation(fullscreenShader, "u_widthrel");
+	GLint heightrelloc = glGetUniformLocation(fullscreenShader, "u_heightrel");
+	glUniform1f(widthloc, Video.ViewportWidth);
+	glUniform1f(heightloc, Video.ViewportHeight);
+	glUniform1f(widthrelloc, (float)Video.Width / (float)Video.ViewportWidth);
+	glUniform1f(heightrelloc, (float)Video.Height / (float)Video.ViewportHeight);
+	glUniform1i(textureloc, 0);
+	glActiveTexture(GL_TEXTURE0);
+	// render the framebuffer texture to a fullscreen quad on the real display
+	glBindTexture(GL_TEXTURE_2D, fullscreenTexture);
+	glBegin(GL_QUADS);
+	glTexCoord2f(0, 0);
+	glVertex2i(0, 0);
+	glTexCoord2f(1, 0);
+	glVertex2i(Video.ViewportWidth, 0);
+	glTexCoord2f(1, 1);
+	glVertex2i(Video.ViewportWidth, Video.ViewportHeight);
+	glTexCoord2f(0, 1);
+	glVertex2i(0, Video.ViewportHeight);
+	glEnd();
+	SDL_GL_SwapBuffers();
+	glUseProgram(0); // Disable shaders again, and render to framebuffer again
+	glBindFramebuffer(GL_FRAMEBUFFER_EXT, fullscreenFramebuffer);
+}
+#endif
\ No newline at end of file