From fed710754296111a51b1b99b40a3c5e5dc873895 Mon Sep 17 00:00:00 2001
From: Adrian Kummerlaender
Date: Tue, 18 Dec 2018 17:04:18 +0100
Subject: Purify collide shader
i.e. move fluid vertex placement to appropriate vertex shader.
Do not amplify or shift fluid moments in any way prior to
passing it to the display pipeline.
---
src/shader/code/collide.glsl | 17 +++++++++--------
src/shader/code/stream.glsl | 4 ++++
src/shader/code/vertex.glsl | 26 ++++++++++++++++++++++++--
src/shader/wrap/graphic_shader.cc | 6 ++++++
src/shader/wrap/graphic_shader.h | 1 +
5 files changed, 44 insertions(+), 10 deletions(-)
(limited to 'src/shader')
diff --git a/src/shader/code/collide.glsl b/src/shader/code/collide.glsl
index cef2549..cbddfa9 100644
--- a/src/shader/code/collide.glsl
+++ b/src/shader/code/collide.glsl
@@ -7,8 +7,6 @@ layout (std430, binding=1) buffer bufferCollide{ float collideCells[]; };
layout (std430, binding=2) buffer bufferStream{ float streamCells[]; };
layout (std430, binding=3) buffer bufferFluid{ float fluidCells[]; };
-const float displayAmplifier = 10.;
-
/// LBM constants
uniform uint nX;
@@ -26,8 +24,8 @@ const float omega = 1/tau;
/// Vector utilities
-float comp(int x, int y, vec2 v) {
- return x*v.x + y*v.y;
+float comp(int i, int j, vec2 v) {
+ return i*v.x + j*v.y;
}
float sq(float x) {
@@ -68,9 +66,9 @@ void set(uint x, uint y, int i, int j, float v) {
void setFluid(uint x, uint y, vec2 v, float d) {
const uint idx = indexOfFluidVertex(x, y);
- fluidCells[idx + 0] = float(x) - nX/2;
- fluidCells[idx + 1] = float(y) - nY/2;
- fluidCells[idx + 2] = displayAmplifier * norm(v);
+ fluidCells[idx + 0] = v.x;
+ fluidCells[idx + 1] = v.y;
+ fluidCells[idx + 2] = norm(v);
}
/// Moments
@@ -101,6 +99,10 @@ void main() {
const uint x = gl_GlobalInvocationID.x;
const uint y = gl_GlobalInvocationID.y;
+ if ( !(x < nX && y < nY) ) {
+ return;
+ }
+
const float d = density(x,y);
const vec2 v = velocity(x,y,d);
@@ -112,6 +114,5 @@ void main() {
set(x,y,i,j, get(x,y,i,j) + omega * (eq - get(x,y,i,j)));
}
}
-
}
)";
diff --git a/src/shader/code/stream.glsl b/src/shader/code/stream.glsl
index 982b207..9b77c85 100644
--- a/src/shader/code/stream.glsl
+++ b/src/shader/code/stream.glsl
@@ -29,6 +29,10 @@ void main() {
const uint x = gl_GlobalInvocationID.x;
const uint y = gl_GlobalInvocationID.y;
+ if ( !(x < nX && y < nY) ) {
+ return;
+ }
+
if ( x != 0 && x != nX-1 && y != 0 && y != nY-1 ) {
for ( int i = -1; i <= 1; ++i ) {
for ( int j = -1; j <= 1; ++j ) {
diff --git a/src/shader/code/vertex.glsl b/src/shader/code/vertex.glsl
index 516f2c6..e132e5f 100644
--- a/src/shader/code/vertex.glsl
+++ b/src/shader/code/vertex.glsl
@@ -7,6 +7,11 @@ out VS_OUT {
vec3 color;
} vs_out;
+uniform uint nX;
+uniform uint nY;
+
+const float displayAmplifier = 10.0;
+
float unit(float x) {
return 1.0/(1.0+exp(-x));
}
@@ -15,8 +20,25 @@ vec3 getColor(float x) {
return x*vec3(1.0,0.0,0.0) + (1-x)*vec3(-0.5,0.0,1.0);
}
+vec2 fluidVertexAtIndex(uint i) {
+ const float y = floor(float(i) / float(nX));
+ return vec2(
+ i - nX*y,
+ y
+ );
+
+}
+
void main() {
- gl_Position = vec4(VertexPosition.xy, 0., 1.);
- vs_out.color = getColor(unit(VertexPosition.z));
+ const vec2 idx = fluidVertexAtIndex(gl_VertexID);
+
+ gl_Position = vec4(
+ idx.x - nX/2,
+ idx.y - nY/2,
+ 0.,
+ 1.
+ );
+
+ vs_out.color = getColor(unit(displayAmplifier * VertexPosition.z));
}
)";
diff --git a/src/shader/wrap/graphic_shader.cc b/src/shader/wrap/graphic_shader.cc
index c891730..20fc222 100644
--- a/src/shader/wrap/graphic_shader.cc
+++ b/src/shader/wrap/graphic_shader.cc
@@ -42,6 +42,12 @@ GLuint GraphicShader::setUniform(const std::string& name, int value) const {
return id;
}
+GLuint GraphicShader::setUniform(const std::string& name, GLuint value) const {
+ GLuint id = util::getUniform(_id, name);
+ glUniform1ui(id, value);
+ return id;
+}
+
GLuint GraphicShader::setUniform(const std::string& name, const std::vector<GLuint>& v) const {
GLuint id = util::getUniform(_id, name);
glUniform1iv(id, v.size(), reinterpret_cast<const GLint*>(v.data()));
diff --git a/src/shader/wrap/graphic_shader.h b/src/shader/wrap/graphic_shader.h
index dcae6db..83fca34 100644
--- a/src/shader/wrap/graphic_shader.h
+++ b/src/shader/wrap/graphic_shader.h
@@ -25,6 +25,7 @@ public:
~GraphicShader();
GLuint setUniform(const std::string& name, int value) const;
+ GLuint setUniform(const std::string& name, GLuint value) const;
GLuint setUniform(const std::string& name, const std::vector<GLuint>& v) const;
GLuint setUniform(const std::string& name, glm::mat4& M) const;
};
--
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