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44 lines
1.5 KiB
GLSL
44 lines
1.5 KiB
GLSL
#version 120
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//
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// metavoxel_heightfield_base.vert
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// vertex shader
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//
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// Created by Andrzej Kapolka on 8/20/14.
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// Copyright 2014 High Fidelity, Inc.
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//
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// Distributed under the Apache License, Version 2.0.
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// See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
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//
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// the height texture
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uniform sampler2D heightMap;
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// the distance between height points in texture space
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uniform float heightScale;
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// the scale between height and color textures
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uniform float colorScale;
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// the interpolated normal
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varying vec4 normal;
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void main(void) {
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// transform and store the normal for interpolation
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vec2 heightCoord = gl_MultiTexCoord0.st;
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float deltaX = texture2D(heightMap, heightCoord - vec2(heightScale, 0.0)).r -
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texture2D(heightMap, heightCoord + vec2(heightScale, 0.0)).r;
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float deltaZ = texture2D(heightMap, heightCoord - vec2(0.0, heightScale)).r -
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texture2D(heightMap, heightCoord + vec2(0.0, heightScale)).r;
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normal = normalize(gl_ModelViewMatrix * vec4(deltaX, heightScale, deltaZ, 0.0));
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// add the height to the position
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float height = texture2D(heightMap, heightCoord).r;
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gl_Position = gl_ModelViewProjectionMatrix * (gl_Vertex + vec4(0.0, height, 0.0, 0.0));
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// the zero height should be invisible
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gl_FrontColor = vec4(1.0, 1.0, 1.0, step(height, 0.0));
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// pass along the scaled/offset texture coordinates
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gl_TexCoord[0] = (gl_MultiTexCoord0 - vec4(heightScale, heightScale, 0.0, 0.0)) * colorScale;
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}
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