105 lines
2.8 KiB
GLSL
105 lines
2.8 KiB
GLSL
/*
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Copyright (c) 2013 yvt
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This file is part of OpenSpades.
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OpenSpades is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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OpenSpades is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with OpenSpades. If not, see <http://www.gnu.org/licenses/>.
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*/
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uniform mat4 projectionViewMatrix;
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uniform mat4 viewMatrix;
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uniform vec3 rightVector;
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uniform vec3 upVector;
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uniform vec3 frontVector;
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uniform vec3 viewOriginVector;
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uniform vec2 zNearFar;
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uniform float fogDistance;
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attribute vec4 positionAttribute;
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attribute vec3 spritePosAttribute;
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attribute vec4 colorAttribute;
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varying vec4 color;
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varying vec4 texCoord;
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varying vec4 fogDensity;
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varying vec4 depthRange;
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vec4 FogDensity(float poweredLength);
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void main() {
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vec3 center = positionAttribute.xyz;
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vec3 pos = center;
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float radius = positionAttribute.w;
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vec3 right = rightVector * radius;
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vec3 up = upVector * radius;
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float angle = spritePosAttribute.z;
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float c = cos(angle), s = sin(angle);
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vec2 sprP;
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sprP.x = dot(spritePosAttribute.xy, vec2(c, -s));
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sprP.y = dot(spritePosAttribute.xy, vec2(s, c));
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sprP *= radius;
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pos += right * sprP.x;
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pos += up * sprP.y;
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// move sprite to the front of the volume
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float centerDepth = dot(center - viewOriginVector, frontVector);
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depthRange.xy = vec2(centerDepth) + vec2(-1., 1.) * radius;
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// clip the volume by the near clip plane
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float frontDepth = depthRange.x;
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frontDepth = max(frontDepth, .3);
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/*if(frontDepth > depthRange.y) // go beyond near clip plane
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discard;*/ // cannot discard in vertex shader...
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frontDepth = min(frontDepth, depthRange.y);
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depthRange.w = frontDepth;
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pos += frontVector * (frontDepth - centerDepth);
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gl_Position = projectionViewMatrix * vec4(pos, 1.);
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color = colorAttribute;
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// sprite texture coord
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texCoord.xy = spritePosAttribute.xy * .5 + .5;
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// depth texture coord
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texCoord.zw = vec2(.5) + (gl_Position.xy / gl_Position.w) * .5;
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// fog.
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// FIXME: cannot gamma correct because sprite may be
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// alpha-blended.
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vec4 viewPos = viewMatrix * vec4(pos,1.);
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vec2 horzRelativePos = pos.xy - viewOriginVector.xy;
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float horzDistance = dot(horzRelativePos, horzRelativePos);
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fogDensity = FogDensity(horzDistance);
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// precompute some value in vertex shader to
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// reduce instruction count in frag. shader
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depthRange.z = 1. / (depthRange.y - depthRange.w);
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depthRange.y = depthRange.x;
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depthRange.x *= -depthRange.z;
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depthRange.y /= (zNearFar.x * zNearFar.y);
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depthRange.z *= (zNearFar.x * zNearFar.y);
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}
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