overte/interface/resources/shaders/metavoxel_voxel_splat.vert
2015-01-02 13:57:27 -08:00

75 lines
2.7 KiB
GLSL

#version 120
//
// metavoxel_voxel_splat.vert
// vertex shader
//
// Created by Andrzej Kapolka on 9/4/14.
// Copyright 2014 High Fidelity, Inc.
//
// Distributed under the Apache License, Version 2.0.
// See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
//
// the splat texture offset
uniform vec3 splatTextureOffset;
// the splat textures scales on the S axis
uniform vec4 splatTextureScalesS;
// the splat texture scales on the T axis
uniform vec4 splatTextureScalesT;
// the lower bounds of the values corresponding to the splat textures
uniform vec4 textureValueMinima;
// the upper bounds of the values corresponding to the splat textures
uniform vec4 textureValueMaxima;
// the materials to apply to the vertex
attribute vec4 materials;
// the weights of each material
attribute vec4 materialWeights;
// the model space normal
varying vec3 normal;
// alpha values for the four splat textures
varying vec4 alphaValues;
void main(void) {
// use the fixed-function position
gl_Position = ftransform();
// pass along the normal
normal = gl_Normal;
// pass along the scaled/offset texture coordinates
vec4 textureSpacePosition = (gl_Vertex.xyz + splatTextureOffset).xyyz;
gl_TexCoord[0] = textureSpacePosition * vec4(splatTextureScalesS[0], splatTextureScalesT[0],
splatTextureScalesS[0], splatTextureScalesT[0]);
gl_TexCoord[1] = textureSpacePosition * vec4(splatTextureScalesS[1], splatTextureScalesT[1],
splatTextureScalesS[1], splatTextureScalesT[1]);
gl_TexCoord[2] = textureSpacePosition * vec4(splatTextureScalesS[2], splatTextureScalesT[2],
splatTextureScalesS[2], splatTextureScalesT[2]);
gl_TexCoord[3] = textureSpacePosition * vec4(splatTextureScalesS[3], splatTextureScalesT[3],
splatTextureScalesS[3], splatTextureScalesT[3]);
// compute the alpha values for each texture
float value = materials[0];
vec4 valueVector = vec4(value, value, value, value);
alphaValues = step(textureValueMinima, valueVector) * step(valueVector, textureValueMaxima) * materialWeights[0];
value = materials[1];
valueVector = vec4(value, value, value, value);
alphaValues += step(textureValueMinima, valueVector) * step(valueVector, textureValueMaxima) * materialWeights[1];
value = materials[2];
valueVector = vec4(value, value, value, value);
alphaValues += step(textureValueMinima, valueVector) * step(valueVector, textureValueMaxima) * materialWeights[2];
value = materials[3];
valueVector = vec4(value, value, value, value);
alphaValues += step(textureValueMinima, valueVector) * step(valueVector, textureValueMaxima) * materialWeights[3];
}