From d4b9ccf499fb8ce8b5098a465a90eb1ad2c64f45 Mon Sep 17 00:00:00 2001
From: vincentlj <vincentlj@178a84e3-b1eb-0310-8ba1-8eac791a3b58>
Date: Mon, 30 Dec 2013 13:57:55 +0000
Subject: [PATCH] GPUParticles: Particles don't follow their source.

git-svn-id: svn+ssh://svn.code.sf.net/p/supertuxkart/code/main/trunk@14838 178a84e3-b1eb-0310-8ba1-8eac791a3b58
---
 data/shaders/pointemitter.vert | 5 +++--
 src/graphics/gpuparticles.cpp  | 7 +++----
 src/graphics/gpuparticles.h    | 2 +-
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/data/shaders/pointemitter.vert b/data/shaders/pointemitter.vert
index b3a236c26..ef3581224 100644
--- a/data/shaders/pointemitter.vert
+++ b/data/shaders/pointemitter.vert
@@ -1,6 +1,6 @@
 #version 130
 uniform int dt;
-uniform vec3 source;
+uniform mat4 sourcematrix;
 uniform int duration;
 
 in vec3 particle_position;
@@ -13,7 +13,8 @@ out vec4 new_particle_velocity;
 
 void main(void)
 {
-  new_particle_position = (lifetime > 0.) ? particle_position + particle_velocity.xyz * float(dt) : vec3(0., 0., 0.);
+  vec4 initialposition = sourcematrix * vec4(0., 0., 0., 1.0);
+  new_particle_position = (lifetime > 0.) ? particle_position + particle_velocity.xyz * float(dt) : initialposition.xyz;
   new_lifetime = (lifetime > 0.) ? lifetime - float(dt) : float(duration);
   new_particle_velocity = particle_velocity;
   gl_Position = vec4(0.);
diff --git a/src/graphics/gpuparticles.cpp b/src/graphics/gpuparticles.cpp
index b698ee884..3eb540b26 100644
--- a/src/graphics/gpuparticles.cpp
+++ b/src/graphics/gpuparticles.cpp
@@ -234,7 +234,7 @@ PointEmitter::PointEmitter(scene::ISceneNode *parent,
   SimulationProgram = LoadTFBProgram(file_manager->getAsset("shaders/pointemitter.vert").c_str(), varyings, 3);
   loc_duration = glGetUniformLocation(SimulationProgram, "duration");
   loc_dt = glGetUniformLocation(SimulationProgram, "dt");
-  loc_source = glGetUniformLocation(SimulationProgram, "source");
+  loc_sourcematrix = glGetUniformLocation(SimulationProgram, "sourcematrix");
   loc_position = glGetAttribLocation(SimulationProgram, "particle_position");
   loc_lifetime = glGetAttribLocation(SimulationProgram, "lifetime");
   loc_velocity = glGetAttribLocation(SimulationProgram, "particle_velocity");
@@ -272,6 +272,7 @@ PointEmitter::PointEmitter(scene::ISceneNode *parent,
 
 void PointEmitter::simulate()
 {
+	core::matrix4 matrix = m_node->getAbsoluteTransformation();
   glUseProgram(SimulationProgram);
   glEnable(GL_RASTERIZER_DISCARD);
   glEnableVertexAttribArray(0);
@@ -285,7 +286,7 @@ void PointEmitter::simulate()
 
   glUniform1i(loc_dt, 1);
   glUniform1i(loc_duration, duration);
-  glUniform3f(loc_source, getPosition().X, getPosition().Y, getPosition().Z);
+  glUniformMatrix4fv(loc_sourcematrix, 1, GL_FALSE, matrix.pointer());
   glBeginTransformFeedback(GL_POINTS);
   glDrawArrays(GL_POINTS, 0, count);
   glEndTransformFeedback();
@@ -298,13 +299,11 @@ void PointEmitter::simulate()
 
 void PointEmitter::draw()
 {
-  updateAbsolutePosition();
   glDisable(GL_ALPHA_TEST);
   glDepthMask(GL_FALSE);
 	glEnable(GL_BLEND);
 	core::matrix4 matrix = irr_driver->getVideoDriver()->getTransform(video::ETS_PROJECTION);
 	matrix *= irr_driver->getVideoDriver()->getTransform(video::ETS_VIEW);
-	matrix *= m_node->getAbsoluteTransformation();
   glEnable(GL_VERTEX_PROGRAM_POINT_SIZE);
   glEnable(GL_POINT_SPRITE);
   glBlendEquation(GL_FUNC_ADD);
diff --git a/src/graphics/gpuparticles.h b/src/graphics/gpuparticles.h
index 1b3bfa958..379745752 100644
--- a/src/graphics/gpuparticles.h
+++ b/src/graphics/gpuparticles.h
@@ -29,7 +29,7 @@ class PointEmitter : public GPUParticle
 {
 protected:
   GLuint SimulationProgram, RenderProgram;
-  GLuint loc_duration, loc_source, loc_dt, loc_matrix, loc_texture, loc_normal_and_depths, loc_screen, loc_invproj;
+  GLuint loc_duration, loc_sourcematrix, loc_dt, loc_matrix, loc_texture, loc_normal_and_depths, loc_screen, loc_invproj;
   GLuint loc_position, loc_velocity, loc_lifetime;
   GLuint tfb_buffers[2];
   GLuint texture, normal_and_depth;