#108: ambient lights now render correctly

Ambient lights had in fact never worked since the switch to GLSL, since the
ambient light code was only ever present in the old Cg shaders. The GLSL shader
is now updated to support ambient lights through a new bool uniform, which
works for both models and brushes.

include/iglprogram.h

@@ -48,28 +48,24 @@ class GLProgram
         /// Transformation from world space into light space
         Matrix4 world2Light;
 
-        /// Amount of directionality, 0.0 for normal light, 1.0 for ambient
-        float ambientFactor;
+        /// True if this is an ambient light, false for a directional light
+        bool isAmbientLight = false;
 
         /// Whether vertex colours should be inverted
-        bool invertVertexColour;
+        bool invertVertexColour = false;
 
         Params(const Vector3& lightOrigin_,
                const Colour4& lightColour_,
                const Matrix4& world2Light_)
         : lightOrigin(lightOrigin_),
           lightColour(lightColour_),
-          world2Light(world2Light_),
-          ambientFactor(0.0),
-          invertVertexColour(false)
+          world2Light(world2Light_)
         {
-
         }
     };
 
 	/**
-	 * \brief
-     * Apply render parameters used by this program to OpenGL.
+	 * \brief Apply render parameters used by this program to OpenGL.
      *
      * This method is invoked shortly before the renderable geometry is
      * submitted for rendering; the GLProgram must apply to the GL state any

install/gl/interaction_fp.glsl

@@ -33,6 +33,9 @@ uniform float		u_light_scale;
 // Invert vertex colour
 uniform bool uInvertVCol;
 
+// Activate ambbient light mode (brightness unaffected by direction)
+uniform bool uAmbientLight;
+
 varying vec3		var_vertex;
 varying vec4		var_tex_diffuse_bump;
 varying vec2		var_tex_specular;
@@ -56,7 +59,8 @@ void	main()
 
 	// compute the diffuse term
 	vec4 diffuse = texture2D(u_diffusemap, var_tex_diffuse_bump.st);
-	diffuse.rgb *= u_light_color * u_light_scale * clamp(dot(N, L), 0.0, 1.0);
+    float lightBrightness = uAmbientLight ? 1.0 : clamp(dot(N, L), 0.0, 1.0);
+	diffuse.rgb *= u_light_color * u_light_scale * lightBrightness;
 
 	// compute the specular term
     float specIntensity = clamp(dot(N, H), 0.0, 1.0);

radiantcore/rendersystem/backend/OpenGLShaderPass.cpp

@@ -691,7 +691,7 @@ void OpenGLShaderPass::setUpLightingCalculation(OpenGLState& current,
     GLProgram::Params parms(
         light->getLightOrigin(), layer->getColour(), world2light
     );
-    parms.ambientFactor = lightMat->isAmbientLight() ? 1.0f : 0.0f;
+    parms.isAmbientLight = lightMat->isAmbientLight();
     parms.invertVertexColour = _glState.isColourInverted();
 
     assert(current.glProgram);

radiantcore/rendersystem/backend/glprogram/GLSLBumpProgram.cpp

@@ -53,9 +53,10 @@ void GLSLBumpProgram::create()
     // Set the uniform locations to the correct bound values
     _locLightOrigin = glGetUniformLocation(_programObj, "u_light_origin");
     _locLightColour = glGetUniformLocation(_programObj, "u_light_color");
-    _locViewOrigin  = glGetUniformLocation(_programObj, "u_view_origin");
-    _locLightScale  = glGetUniformLocation(_programObj, "u_light_scale");
-    _locInvertVCol  = glGetUniformLocation(_programObj, "uInvertVCol");
+    _locViewOrigin = glGetUniformLocation(_programObj, "u_view_origin");
+    _locLightScale = glGetUniformLocation(_programObj, "u_light_scale");
+    _locInvertVCol = glGetUniformLocation(_programObj, "uInvertVCol");
+    _locAmbientLight = glGetUniformLocation(_programObj, "uAmbientLight");
 
     // Set up the texture uniforms. The renderer uses fixed texture units for
     // particular textures, so make sure they are correct here.
@@ -155,6 +156,7 @@ void GLSLBumpProgram::applyRenderParams(const Vector3& viewer,
         static_cast<float>(parms.lightColour.z())
     );
     glUniform1f(_locLightScale, _lightScale);
+    glUniform1i(_locAmbientLight, parms.isAmbientLight);
 
     // Set vertex colour parameters
     glUniform1i(_locInvertVCol, parms.invertVertexColour);

radiantcore/rendersystem/backend/glprogram/GLSLBumpProgram.h

@@ -18,7 +18,7 @@ class GLSLBumpProgram
     int _locLightColour;
     int _locViewOrigin;
     int _locLightScale;
-    int _locAmbientFactor;
+    int _locAmbientLight;
     int _locInvertVCol;
 
     // Program object identifier