/**
 ** Supermodel
 ** A Sega Model 3 Arcade Emulator.
 ** Copyright 2011 Bart Trzynadlowski, Nik Henson 
 **
 ** This file is part of Supermodel.
 **
 ** Supermodel is free software: you can redistribute it and/or modify it under
 ** the terms of the GNU General Public License as published by the Free 
 ** Software Foundation, either version 3 of the License, or (at your option)
 ** any later version.
 **
 ** Supermodel is distributed in the hope that it will be useful, but WITHOUT
 ** ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 ** FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 ** more details.
 **
 ** You should have received a copy of the GNU General Public License along
 ** with Supermodel.  If not, see <http://www.gnu.org/licenses/>.
 **/
 
/*
 * Shaders3D.h
 * 
 * Header file containing the 3D vertex and fragment shaders.
 */

#ifndef INCLUDED_SHADERS3D_H
#define INCLUDED_SHADERS3D_H

// Vertex shader
static const char vertexShaderSource[] =
{
"/**\n"
" ** Supermodel\n"
" ** A Sega Model 3 Arcade Emulator.\n"
" ** Copyright 2011 Bart Trzynadlowski, Nik Henson \n"
" **\n"
" ** This file is part of Supermodel.\n"
" **\n"
" ** Supermodel is free software: you can redistribute it and/or modify it under\n"
" ** the terms of the GNU General Public License as published by the Free \n"
" ** Software Foundation, either version 3 of the License, or (at your option)\n"
" ** any later version.\n"
" **\n"
" ** Supermodel is distributed in the hope that it will be useful, but WITHOUT\n"
" ** ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or\n"
" ** FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for\n"
" ** more details.\n"
" **\n"
" ** You should have received a copy of the GNU General Public License along\n"
" ** with Supermodel.  If not, see <http://www.gnu.org/licenses/>.\n"
" **/\n"
"  \n"
"/*\n"
" * Vertex.glsl\n"
" *\n"
" * Vertex shader for 3D rendering.\n"
" */\n"
" \n"
"#version 120\n"
"\n"
"// Global uniforms\n"
"uniform mat4\tmodelViewMatrix;\t// model -> view space matrix\n"
"uniform mat4\tprojectionMatrix;\t// view space -> screen space matrix\n"
"uniform vec3\tlighting[2];\t\t// lighting state (lighting[0] = sun direction, lighting[1].x,y = diffuse, ambient intensities from 0-1.0)\n"
"uniform vec4\tspotEllipse;\t\t// spotlight ellipse position: .x=X position (normalized device coordinates), .y=Y position, .z=half-width, .w=half-height)\n"
"uniform vec2\tspotRange;\t\t\t// spotlight Z range: .x=start (viewspace coordinates), .y=limit\n"
"uniform vec3\tspotColor;\t\t\t// spotlight RGB color\n"
"\n"
"// Custom vertex attributes\n"
"attribute vec4\tsubTexture;\t\t// .x=texture X, .y=texture Y, .z=texture width, .w=texture height (all in texels)\n"
"attribute vec4\ttexParams;\t\t// .x=texture enable (if 1, else 0), .y=use transparency (if >=0), .z=U wrap mode (1=mirror, 0=repeat), .w=V wrap mode\n"
"attribute float\ttexFormat;\t\t// T1RGB5 contour texture (if > 0)\n"
"attribute float\ttransLevel;\t\t// translucence level, 0.0 (transparent) to 1.0 (opaque). if less than 1.0, replace alpha value\n"
"attribute float\tlightEnable;\t// lighting enabled (1.0) or luminous (0.0), drawn at full intensity\n"
"attribute float\tshininess;\t\t// specular shininess (if >= 0.0) or disable specular lighting (negative)\n"
"attribute float\tfogIntensity;\t// fog intensity (1.0, full fog effect, 0.0, no fog) \n"
"\n"
"// Custom outputs to fragment shader\n"
"varying vec4\tfsSubTexture;\n"
"varying vec4\tfsTexParams;\n"
"varying float\tfsTexFormat;\n"
"varying float\tfsTransLevel;\n"
"varying vec3\tfsLightIntensity;\t// total light intensity for this vertex\n"
"varying float\tfsSpecularTerm;\t\t// specular light term (additive)\n"
"varying float\tfsFogFactor;\t\t// fog factor\n"
"varying float\tfsViewZ;\n"
"\n"
"// Gets the 3x3 matrix out of a 4x4 (because mat3(mat4matrix) does not work on ATI!)\n"
"mat3 GetLinearPart( mat4 m )\n"
"{\n"
"\tmat3 result;\n"
"\t\n"
"\tresult[0][0] = m[0][0]; \n"
"\tresult[0][1] = m[0][1]; \n"
"\tresult[0][2] = m[0][2]; \n"
"\n"
"\tresult[1][0] = m[1][0]; \n"
"\tresult[1][1] = m[1][1]; \n"
"\tresult[1][2] = m[1][2]; \n"
"\t\n"
"\tresult[2][0] = m[2][0]; \n"
"\tresult[2][1] = m[2][1]; \n"
"\tresult[2][2] = m[2][2]; \n"
"\t\n"
"\treturn result;\n"
"}\n"
"\n"
"void main(void)\n"
"{\n"
"\tvec3\tviewVertex;\t\t// vertex coordinates in view space\n"
"\tvec3\tviewNormal;\t\t// vertex normal in view space\n"
"\tvec3\tsunVector;\t\t// sun lighting vector (as reflecting away from vertex)\n"
"\tfloat\tsunFactor;\t\t// sun light projection along vertex normal (0.0 to 1.0)\n"
"\tvec3\thalfway;\n"
"\tfloat\tspecFactor;\n"
"\t\n"
"\t// Transform vertex\n"
"\tgl_Position = projectionMatrix * modelViewMatrix * gl_Vertex;\n"
"\tviewVertex = vec3(modelViewMatrix * gl_Vertex);\t\n"
"\t\n"
"\t/*\n"
"\t * Modulation\n"
"\t *\n"
" \t * Polygon color serves as material color (modulating the light intensity)\n"
"\t * for textured polygons. The fragment shader will ignore (overwrite) the\n"
"\t * the color passed to it if the fragment is textured. \n"
"\t *\n"
"\t * Untextured fragments must be set to the polygon color and the light\n"
"\t * intensity is initialized to 1.0 here. Alpha must be set to 1.0 because\n"
"\t * the fragment shader multiplies it by the polygon translucency setting. \n"
"\t *\n"
"\t * TO-DO: Does OpenGL set alpha to 1.0 by default if no alpha is specified\n"
"\t * for the vertex? If so, we can remove that line from here.\n"
"\t */\n"
"\n"
"\tgl_FrontColor = gl_Color;\t// untextured polygons will use this\n"
"\tgl_FrontColor.a = 1.0;\t\n"
"\tfsLightIntensity = vec3(1.0,1.0,1.0);\n"
"\tif (texParams.x > 0.5)\t\t// textured\n"
"\t\tfsLightIntensity *= gl_Color.rgb;\n"
"\t\t\n"
"\t/*\n"
" \t * Sun Light\n"
"\t *\n"
"\t * Parallel light source and ambient lighting are only applied for non-\n"
"\t * luminous polygons.\n"
" \t */\n"
"\tfsSpecularTerm = 0.0;\n"
" \tif (lightEnable > 0.5)\t// not luminous\n"
"\t{\n"
"\t\t// Normal -> view space\n"
"\t\tviewNormal = normalize(GetLinearPart(modelViewMatrix)*gl_Normal);\n"
"\n"
"\t\t// Real3D -> OpenGL view space convention (TO-DO: do this outside of shader)\n"
"\t\tsunVector = lighting[0]*vec3(1.0,-1.0,-1.0);\n"
"\t\t\n"
"\t\t// Compute diffuse factor for sunlight\n"
"\t\tsunFactor = max(dot(sunVector,viewNormal),0.0);\n"
"\t\t\n"
"\t\t// Total light intensity: sum of all components\n"
"\t\tfsLightIntensity *= (sunFactor*lighting[1].x+lighting[1].y);\n"
"\t\t\n"
"\t\t/*\n"
"\t\t * Specular Lighting\n"
"\t\t *\n"
"\t\t * The specular term is treated similarly to the \"separate specular\n"
"\t\t * color\" functionality of OpenGL: it is added as a highlight in the\n"
"\t\t * fragment shader. This allows even black textures to be lit.\n"
"\t\t *\n"
"\t\t * TO-DO: Ambient intensity viewport parameter is known but what about\n"
"\t\t * the intensity of the specular term? Always applied with full \n"
"\t\t * intensity here but this is unlikely to be correct.\n"
"\t\t */\n"
"  \t\tif (shininess >= 0.0)\n"
"  \t\t{\n"
"  \t\t\t// Standard specular lighting equation\n"
"  \t\t\tvec3 V = normalize(-viewVertex);\n"
"  \t\t\tvec3 H = normalize(sunVector+V);\t// halfway vector\n"
"  \t\t\tfloat s = max(10,64-shininess);\t\t// seems to look nice, but probably not correct\n"
"  \t\t\tfsSpecularTerm = pow(max(dot(viewNormal,H),0),s);\n"
"  \t\t\tif (sunFactor <= 0) fsSpecularTerm = 0;\n"
"  \t\t\t\n"
"  \t\t\t// Faster approximation  \t\t\t\n"
"  \t\t\t//float temp = max(dot(viewNormal,H),0);\n"
"  \t\t\t//float s = 64-shininess;\n"
"  \t\t\t//fsSpecularTerm = temp/(s-temp*s+temp);\n"
"  \t\t\t\n"
"  \t\t\t// Phong formula\n"
"  \t\t\t//vec3 R = normalize(2*dot(sunVector,viewNormal)*viewNormal - sunVector);\n"
"  \t\t\t//vec3 V = normalize(-viewVertex);\n"
"  \t\t\t//float s = max(2,64-shininess);\n"
"  \t\t\t//fsSpecularTerm = pow(max(dot(R,V),0),s);\n"
"  \t\t}\n"
"\t}\n"
"\t\n"
"\t// Fog\n"
"\tfloat z = length(viewVertex);\n"
"\tfsFogFactor = clamp(1.0-fogIntensity*(gl_Fog.start+z*gl_Fog.density), 0.0, 1.0);\n"
"\n"
"\t// Pass viewspace Z coordinate (for spotlight)\n"
"\tfsViewZ = -viewVertex.z;\t// convert Z from GL->Real3D convention (want +Z to be further into screen)\n"
"\n"
"\t// Pass remaining parameters to fragment shader\n"
"\tgl_TexCoord[0] = gl_MultiTexCoord0;\n"
"\tfsSubTexture = subTexture;\n"
"\tfsTexParams = texParams;\n"
"\tfsTransLevel = transLevel;\n"
"\tfsTexFormat = texFormat;\n"
"}\n"
};
	
	
// Fragment shader
static const char fragmentShaderSource[] = 
{
"/**\n"
" ** Supermodel\n"
" ** A Sega Model 3 Arcade Emulator.\n"
" ** Copyright 2011 Bart Trzynadlowski, Nik Henson \n"
" **\n"
" ** This file is part of Supermodel.\n"
" **\n"
" ** Supermodel is free software: you can redistribute it and/or modify it under\n"
" ** the terms of the GNU General Public License as published by the Free \n"
" ** Software Foundation, either version 3 of the License, or (at your option)\n"
" ** any later version.\n"
" **\n"
" ** Supermodel is distributed in the hope that it will be useful, but WITHOUT\n"
" ** ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or\n"
" ** FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for\n"
" ** more details.\n"
" **\n"
" ** You should have received a copy of the GNU General Public License along\n"
" ** with Supermodel.  If not, see <http://www.gnu.org/licenses/>.\n"
" **/\n"
" \n"
"/*\n"
" * Fragment.glsl\n"
" *\n"
" * Fragment shader for 3D rendering.\n"
" */\n"
"\n"
"#version 120\n"
"\n"
"// Global uniforms\n"
"uniform sampler2D\ttextureMap;\t\t// complete texture map, 2048x2048 texels\n"
"uniform vec4\tspotEllipse;\t\t// spotlight ellipse position: .x=X position (screen coordinates), .y=Y position, .z=half-width, .w=half-height)\n"
"uniform vec2\tspotRange;\t\t\t// spotlight Z range: .x=start (viewspace coordinates), .y=limit\n"
"uniform vec3\tspotColor;\t\t\t// spotlight RGB color\n"
"uniform vec3\tlighting[2];\t\t// lighting state (lighting[0] = sun direction, lighting[1].x,y = diffuse, ambient intensities from 0-1.0)\n"
"\n"
"// Inputs from vertex shader \n"
"varying vec4\t\tfsSubTexture;\t// .x=texture X, .y=texture Y, .z=texture width, .w=texture height (all in texels)\n"
"varying vec4\t\tfsTexParams;\t// .x=texture enable (if 1, else 0), .y=use transparency (if > 0), .z=U wrap mode (1=mirror, 0=repeat), .w=V wrap mode\n"
"varying float\t\tfsTexFormat;\t// T1RGB5 contour texture (if > 0)\n"
"varying float\t\tfsTransLevel;\t// translucence level, 0.0 (transparent) to 1.0 (opaque)\n"
"varying vec3\t\tfsLightIntensity;\t// lighting intensity \n"
"varying float\t\tfsSpecularTerm;\t// specular highlight\n"
"varying float\t\tfsFogFactor;\t// fog factor\n"
"varying float\t\tfsViewZ;\t\t// Z distance to fragment from viewpoint at origin\n"
"\n"
"/*\n"
" * WrapTexelCoords():\n"
" *\n"
" * Computes the normalized OpenGL S,T coordinates within the 2048x2048 texture\n"
" * sheet, taking into account wrapping behavior.\n"
" *\n"
" * Computing normalized OpenGL texture coordinates (0 to 1) within the \n"
" * Real3D texture sheet:\n"
" *\n"
" * If the texture is not mirrored, we simply have to clamp the\n"
" * coordinates to fit within the texture dimensions, add the texture\n"
" * X, Y position to select the appropriate one, and normalize by 2048\n"
" * (the dimensions of the Real3D texture sheet).\n"
" *\n"
" *\t\t= [(u,v)%(w,h)+(x,y)]/(2048,2048)\n"
" *\n"
" * If mirroring is enabled, textures are mirrored every odd multiple of\n"
" * the original texture. To detect whether we are in an odd multiple, \n"
" * simply divide the coordinate by the texture dimension and check \n"
" * whether the result is odd. Then, clamp the coordinates as before but\n"
" * subtract from the last texel to mirror them:\n"
" *\n"
" * \t\t= [M*((w-1,h-1)-(u,v)%(w,h)) + (1-M)*(u,v)%(w,h) + (x,y)]/(2048,2048)\n"
" *\t\twhere M is 1.0 if the texture must be mirrored.\n"
" *\n"
" * As an optimization, this function computes TWO texture coordinates\n"
" * simultaneously. The first is texCoord.xy, the second is in .zw. The other\n"
" * parameters must have .xy = .zw.\n"
" */\n"
"vec4 WrapTexelCoords(vec4 texCoord, vec4 texOffset, vec4 texSize, vec4 mirrorEnable)\n"
"{\n"
"\tvec4\tclampedCoord, mirror, glTexCoord;\n"
"\t\n"
"\tclampedCoord = mod(texCoord,texSize);\t\t\t\t\t\t// clamp coordinates to within texture size\n"
"\tmirror = mirrorEnable * mod(floor(texCoord/texSize),2.0);\t// whether this texel needs to be mirrored\n"
"\n"
"\tglTexCoord = (\tmirror*(texSize-clampedCoord) +\n"
"\t\t\t\t\t(vec4(1.0,1.0,1.0,1.0)-mirror)*clampedCoord +\n"
"\t\t\t\t\ttexOffset\n"
"\t\t\t\t ) / 2048.0;\n"
"\treturn glTexCoord;\n"
"}\n"
"\n"
"/*\n"
" * main():\n"
" *\n"
" * Fragment shader entry point.\n"
" */\n"
"\n"
"void main(void)\n"
"{\t\n"
"\tvec4\tuv_top, uv_bot, c[4];\n"
"\tvec2\tr;\n"
"\tvec4\tfragColor;\n"
"\tvec2\tellipse;\n"
"\tvec3\tlightIntensity;\n"
"\tfloat\tinsideSpot;\n"
"\tint\t\tx;\n"
"\t\n"
"\t// Get polygon color for untextured polygons (textured polygons will overwrite)\n"
"\tif (fsTexParams.x < 0.5)\n"
"\t\tfragColor = gl_Color;\t\t\n"
"\telse\n"
"\t// Textured polygons: set fragment color to texel value\n"
"\t{\t\t\t\n"
"\t\t/*\n"
"\t\t * Bilinear Filtering\n"
"\t\t *\n"
"\t\t * In order to get this working on ATI, the number of operations is\n"
"\t\t * reduced by putting everything into vec4s. uv_top holds the UV \n"
"\t\t * coordinates for the top two texels (.xy=left, .zw=right) and uv_bot\n"
"\t\t * is for the lower two.\n"
"\t\t */\n"
"\n"
"\t\t// Compute fractional blending factor, r, and lower left corner of texel 0\n"
"\t\tuv_bot.xy = gl_TexCoord[0].st-vec2(0.5,0.5);\t// move into the lower left blending texel \n"
"\t\tr = uv_bot.xy-floor(uv_bot.xy);\t\t\t\t\t// fractional part\n"
"\t\tuv_bot.xy = floor(uv_bot.xy);\t\t\t\t\t// integral part\n"
"\t\t\n"
"\t\t// Compute texel coordinates\n"
"\t\tuv_bot.xy += vec2(0.5,0.5);\t// offset to center of pixel (should not be needed but it fixes a lot of glitches, esp. on Nvidia)\n"
"\t\tuv_bot.zw = uv_bot.xy + vec2(1.0,0.0);\t\t\t// compute coordinates of the other three neighbors\n"
"\t\tuv_top = uv_bot + vec4(0.0,1.0,0.0,1.0);\n"
"\n"
"\t\t// Compute the properly wrapped texel coordinates\n"
"\t\tuv_top = WrapTexelCoords(uv_top,vec4(fsSubTexture.xy,fsSubTexture.xy),vec4(fsSubTexture.zw,fsSubTexture.zw), vec4(fsTexParams.zw,fsTexParams.zw));\n"
"\t\tuv_bot = WrapTexelCoords(uv_bot,vec4(fsSubTexture.xy,fsSubTexture.xy),vec4(fsSubTexture.zw,fsSubTexture.zw), vec4(fsTexParams.zw,fsTexParams.zw));\n"
"\n"
"\t\t// Fetch the texels\n"
"\t\tc[0]=texture2D(textureMap,uv_bot.xy);\t// bottom-left (base texel)\n"
"\t\tc[1]=texture2D(textureMap,uv_bot.zw);\t// bottom-right\n"
"\t\tc[2]=texture2D(textureMap,uv_top.xy);\t// top-left\n"
"\t\tc[3]=texture2D(textureMap,uv_top.zw);\t// top-right\t\t\n"
"\n"
"\t\t// Interpolate texels and blend result with material color to determine final (unlit) fragment color\n"
"\t\t// fragColor = (c[0]*(1.0-r.s)*(1.0-r.t) + c[1]*r.s*(1.0-r.t) + c[2]*(1.0-r.s)*r.t + c[3]*r.s*r.t);\n"
"\t\t// Faster method:\n"
"\t\tc[0] += (c[1]-c[0])*r.s;\t\t\t// 2 alu\n"
"\t\tc[2] += (c[3]-c[2])*r.s;\t\t\t// 2 alu\n"
"\t\tfragColor = c[0]+(c[2]-c[0])*r.t;\t//2 alu\n"
"\t\n"
"\t\t/*\n"
"\t\t * T1RGB5:\n"
"\t\t *\n"
"\t\t * The transparency bit determines whether to discard pixels (if set).\n"
"\t\t * What is unknown is how this bit behaves when interpolated. OpenGL\n"
"\t\t * processes it as an alpha value, so it might concievably be blended\n"
"\t\t * with neighbors. Here, an arbitrary threshold is chosen.\n"
"\t\t *\n"
"\t\t * To-do: blending could probably enabled and this would work even\n"
"\t\t * better with a hard threshold.\n"
"\t\t *\n"
"\t\t * Countour processing also seems to be enabled for RGBA4 textures.\n"
"\t\t * When the alpha value is 0.0 (or close), pixels are discarded \n"
"\t\t * entirely.\n"
"\t\t */\n"
"\t\tif (fsTexParams.y > 0.5)\t// contour processing enabled\n"
"\t\t{\n"
"\t\t\tif (fragColor.a < 0.01)\t// discard anything with alpha == 0\n"
"\t\t\t\tdiscard;\n"
"\t\t}\n"
"\t\t\n"
"\t\t// If contour texture and not discarded, force alpha to 1.0 because will later be modified by polygon translucency\n"
"\t\tif (fsTexFormat < 0.5)\t\t// contour (T1RGB5) texture map\n"
"\t\t\tfragColor.a = 1.0;\n"
"\t}\n"
"\n"
"\t// Compute spotlight and apply lighting\n"
"\tellipse = (gl_FragCoord.xy-spotEllipse.xy)/spotEllipse.zw;\n"
"\tinsideSpot = dot(ellipse,ellipse);\n"
"\tif ((insideSpot <= 1.0) &&  (fsViewZ>=spotRange.x) && (fsViewZ<spotRange.y))\n"
"\t\tlightIntensity = fsLightIntensity+(1.0-insideSpot)*spotColor;\n"
"\telse\n"
"\t\tlightIntensity = fsLightIntensity;\n"
"\tfragColor.rgb *= lightIntensity;\n"
"\tfragColor.rgb += vec3(fsSpecularTerm,fsSpecularTerm,fsSpecularTerm);\n"
"\t\n"
"\t// Translucency (modulates existing alpha channel for RGBA4 texels)\n"
"\tfragColor.a *= fsTransLevel;\n"
"\n"
"\t// Apply fog under the control of fog factor setting from polygon header\n"
"\tfragColor.rgb = mix(gl_Fog.color.rgb, fragColor.rgb, fsFogFactor);\n"
"\n"
"\t// Store final color\n"
"\tgl_FragColor = fragColor;\n"
"}\n"
};

#endif	// INCLUDED_SHADERS3D_H