Added simple geometry shader which draws a red triangle which changes it's height over time.

data/levels/Compositions.xml

@@ -75,7 +75,7 @@
         <gColour>1.0</gColour>
         <bColour>1.0</bColour>
         <intensity>4.0</intensity>
-        <flameOffset>0.5</flameOffset>
+        <flameOffset>-1.2</flameOffset>
     </light>
 </composition>
 

data/shader/flame.fsh

@@ -0,0 +1,7 @@
+#version 150
+
+out vec4 oColor;
+
+void main() {
+    oColor = vec4(1.0, 0.0, 0.0, 0.5);
+}

data/shader/flame.gsh

@@ -0,0 +1,20 @@
+#version 150
+
+uniform mat4 viewProjectionMatrix;
+uniform float time;
+
+layout(points) in;
+layout(triangle_strip, max_vertices = 3) out;
+
+void main() {
+    gl_Position = gl_in[0].gl_Position + viewProjectionMatrix * vec4(-0.5, 0.0, 0.0, 0.0);
+    EmitVertex();
+
+    gl_Position = gl_in[0].gl_Position + viewProjectionMatrix * vec4(0.5, 0.0, 0.0, 0.0);
+    EmitVertex();
+
+    gl_Position = gl_in[0].gl_Position + viewProjectionMatrix * vec4(0.0, 2.0 + sin(time), 0.0, 0.0);
+    EmitVertex();
+
+    EndPrimitive();
+}

data/shader/flame.vsh

@@ -0,0 +1,9 @@
+#version 150
+
+uniform mat4 viewProjectionMatrix;
+
+in vec3 aPosition;
+
+void main () {
+    gl_Position = viewProjectionMatrix * vec4(aPosition, 1.0);
+}

graphics.cc

@@ -49,6 +49,15 @@ void Graphics::init(Level* level) {
     depthCubeShader = ShaderProgramCreator("depth_cube")
         .attributeLocations(vao->getAttributeLocations()).create();
 
+    flame_positions_ab = SharedArrayBuffer(new ArrayBuffer());
+    flame_positions_ab->defineAttribute("aPosition", GL_FLOAT, 3);
+    flame_positions = SharedVertexArrayObject(new VertexArrayObject());
+    flame_positions->setMode(GL_POINTS);
+    flame_positions->attachAllAttributes(flame_positions_ab);
+
+    flameShader = ShaderProgramCreator("flame")
+        .attributeLocations(flame_positions->getAttributeLocations()).create();
+
     depthTexture = SharedTexture2D( new Texture2D(windowSize, GL_DEPTH_COMPONENT24));
     depthTexture->setMinFilter(GL_NEAREST);
     depthTexture->setMagFilter(GL_NEAREST);
@@ -157,7 +166,7 @@ void Graphics::render(double time)
     double nextUpdate = lastUpdate + lightUpdateDelay;
     if (time >= nextUpdate)
     {
-        updateShaderLights();
+        updateLights();
         lastUpdate = time;
     }
     
@@ -187,6 +196,12 @@ void Graphics::render(double time)
     
     // render the level
     level->render(lightingShader, true, &lightingViewProjectionMatrix, &shadowVPs);
+
+    // draw flames on top
+    flameShader->use();
+    flameShader->setUniform("viewProjectionMatrix", lightingViewProjectionMatrix);
+    flameShader->setUniform("time", (float) time);
+    flame_positions->render();
 }
 
 bool Graphics::compareLightDistances(Light a, Light b) {
@@ -210,7 +225,7 @@ void Graphics::updateClosestLights() {
     }
 }
 
-void Graphics::updateShaderLights() {
+void Graphics::updateLights() {
     updateClosestLights();
     if (closestLights.size() > 0) {
         lightingShader->setUniform("lightCount", (int) closestLights.size());
@@ -247,6 +262,17 @@ void Graphics::updateShaderLights() {
         lightingShader->setUniform("directionalIntensity",
             level->getDirectionalLight()->getIntensity());
     }
+    float flamePositionsData[closestLights.size() * 3] = {};
+    int flameIndex = 0;
+    for (unsigned int i = 0; i<closestLights.size(); i++) {
+        if (closestLights.at(i).getFlameYOffset() != 0.0f) {
+            flamePositionsData[flameIndex + 0] = closestLights.at(i).getPosition().x;
+            flamePositionsData[flameIndex + 1] = closestLights.at(i).getPosition().y + closestLights.at(i).getFlameYOffset();
+            flamePositionsData[flameIndex + 2] = closestLights.at(i).getPosition().z;
+            flameIndex+=3;
+        }
+    }
+    flame_positions_ab->setDataElements(flameIndex, flamePositionsData);
 }
 
 void Graphics::resize(glm::uvec2 windowSize) {

graphics.hh

@@ -19,7 +19,7 @@ class Graphics {
         void resize(glm::uvec2 windowSize);
         float getFarPlane();
     private:
-        void updateShaderLights();
+        void updateLights();
         void updateClosestLights();
         bool compareLightDistances(Light a, Light b);
         void saveDepthBufferToDisk(int face, std::string);
@@ -31,10 +31,13 @@ class Graphics {
         ACGL::OpenGL::SharedShaderProgram lightingShader;
         ACGL::OpenGL::SharedShaderProgram depthCubeShader;
         ACGL::OpenGL::SharedShaderProgram depthShader;
+        ACGL::OpenGL::SharedShaderProgram flameShader;
         ACGL::OpenGL::SharedTexture2D depthTexture;
         ACGL::OpenGL::SharedFrameBufferObject framebuffer;
         std::vector<ACGL::OpenGL::SharedTextureCubeMap> depth_cubeMaps;
         ACGL::OpenGL::SharedFrameBufferObject framebuffer_cube;
+        ACGL::OpenGL::SharedVertexArrayObject flame_positions;
+        ACGL::OpenGL::SharedArrayBuffer flame_positions_ab;
         int cube_size;
         unsigned int maxShadowRenderCount;
         Level* level;