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Compute heightfield normals from adjacent values in vertex shader.

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This commit is contained in:
Andrzej Kapolka 2014-08-05 15:13:50 -07:00
parent 96302ca271
commit 4696832ec6
3 changed files with 17 additions and 2 deletions
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12
interface/resources/shaders/metavoxel_heightfield.vert
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@ -14,18 +14,26 @@
// the height texture
uniform sampler2D heightMap;
// the distance between height points in texture space
uniform float heightScale;
// the interpolated normal
varying vec4 normal;
void main(void) {
// transform and store the normal for interpolation
normal = normalize(gl_ModelViewMatrix * vec4(0.0, 1.0, 0.0, 0.0));
vec2 heightCoord = gl_MultiTexCoord0.st;
float deltaX = texture2D(heightMap, heightCoord - vec2(heightScale, 0.0)).r -
texture2D(heightMap, heightCoord + vec2(heightScale, 0.0)).r;
float deltaZ = texture2D(heightMap, heightCoord - vec2(0.0, heightScale)).r -
texture2D(heightMap, heightCoord + vec2(0.0, heightScale)).r;
normal = normalize(gl_ModelViewMatrix * vec4(deltaX, heightScale, deltaZ, 0.0));
// pass along the texture coordinates
gl_TexCoord[0] = gl_MultiTexCoord0;
// add the height to the position
float height = texture2D(heightMap, gl_MultiTexCoord0.st).r;
float height = texture2D(heightMap, heightCoord).r;
gl_Position = gl_ModelViewProjectionMatrix * (gl_Vertex + vec4(0.0, height, 0.0, 0.0));
// the zero height should be invisible

5
interface/src/MetavoxelSystem.cpp
View file

@ -388,6 +388,9 @@ void HeightfieldBuffer::render() {
glActiveTexture(GL_TEXTURE1);
glBindTexture(GL_TEXTURE_2D, _colorTextureID);
DefaultMetavoxelRendererImplementation::getHeightfieldProgram().setUniformValue(
DefaultMetavoxelRendererImplementation::getHeightScaleLocation(), 1.0f / _heightSize);
glDrawRangeElements(GL_QUADS, 0, vertexCount - 1, indexCount, GL_UNSIGNED_INT, 0);
glBindTexture(GL_TEXTURE_2D, 0);
@ -470,6 +473,7 @@ void DefaultMetavoxelRendererImplementation::init() {
_heightfieldProgram.bind();
_heightfieldProgram.setUniformValue("heightMap", 0);
_heightfieldProgram.setUniformValue("diffuseMap", 1);
_heightScaleLocation = _heightfieldProgram.uniformLocation("heightScale");
_heightfieldProgram.release();
}
}
@ -766,6 +770,7 @@ void DefaultMetavoxelRendererImplementation::render(MetavoxelData& data, Metavox
ProgramObject DefaultMetavoxelRendererImplementation::_pointProgram;
int DefaultMetavoxelRendererImplementation::_pointScaleLocation;
ProgramObject DefaultMetavoxelRendererImplementation::_heightfieldProgram;
int DefaultMetavoxelRendererImplementation::_heightScaleLocation;
static void enableClipPlane(GLenum plane, float x, float y, float z, float w) {
GLdouble coefficients[] = { x, y, z, w };

2
interface/src/MetavoxelSystem.h
View file

@ -191,6 +191,7 @@ public:
static void init();
static ProgramObject& getHeightfieldProgram() { return _heightfieldProgram; }
static int getHeightScaleLocation() { return _heightScaleLocation; }
Q_INVOKABLE DefaultMetavoxelRendererImplementation();
@ -204,6 +205,7 @@ private:
static int _pointScaleLocation;
static ProgramObject _heightfieldProgram;
static int _heightScaleLocation;
};
/// Base class for spanner renderers; provides clipping.