Multiple point lights

enginecustom/Light.ps

@@ -2,6 +2,10 @@
 // Filename: light.ps
 ////////////////////////////////////////////////////////////////////////////////
 
+/////////////
+// DEFINES //
+/////////////
+#define NUM_LIGHTS 4
 
 /////////////
 // GLOBALS //
@@ -11,13 +15,17 @@ SamplerState SampleType : register(s0);
 cbuffer LightBuffer
 {
     float4 ambientColor;
-    float4 diffuseColor;
     float3 lightDirection;
     float padding;
     float specularPower;
     float4 specularColor;
 };
 
+cbuffer LightColorBuffer
+{
+    float4 diffuseColor[NUM_LIGHTS];
+};
+
 
 //////////////
 // TYPEDEFS //
@@ -27,7 +35,7 @@ struct PixelInputType
     float4 position : SV_POSITION;
     float2 tex : TEXCOORD0;
     float3 normal : NORMAL;
-    float3 viewDirection : TEXCOORD1;
+    float3 lightPos[NUM_LIGHTS] : TEXCOORD1;
 };
 
 
@@ -38,48 +46,39 @@ float4 LightPixelShader(PixelInputType input) : SV_TARGET
 {
     float4 textureColor;
     float3 lightDir;
-    float lightIntensity;
     float4 color;
     float3 reflection;
     float4 specular;
-
+    float lightIntensity[NUM_LIGHTS];
+    float4 colorArray[NUM_LIGHTS];
+    float4 colorSum;
+    int i;
 
     // Sample the pixel color from the texture using the sampler at this texture coordinate location.
     textureColor = shaderTexture.Sample(SampleType, input.tex);
 
-    // Set the default output color to the ambient light value for all pixels.
-    color = ambientColor;
-
-    // Initialize the specular color.
-    specular = float4(0.0f, 0.0f, 0.0f, 0.0f);
-
-
-	// Invert the light direction for calculations.
-    lightDir = -lightDirection;
-
-    // Calculate the amount of light on this pixel.
-    lightIntensity = saturate(dot(input.normal, lightDir));
-
-      if(lightIntensity > 0.0f)
+    for(i=0; i<NUM_LIGHTS; i++)
     {
-        // Determine the final diffuse color based on the diffuse color and the amount of light intensity.
-        color += (diffuseColor * lightIntensity);
+        // Calculate the different amounts of light on this pixel based on the positions of the lights.
+        lightIntensity[i] = saturate(dot(input.normal, input.lightPos[i]));
 
-        // Saturate the ambient and diffuse color.
-        color = saturate(color);
+        // Determine the diffuse color amount of each of the four lights.
+        colorArray[i] = diffuseColor[i] * lightIntensity[i];
+    } 
 
-        // Calculate the reflection vector based on the light intensity, normal vector, and light direction.
-        reflection = normalize(2.0f * lightIntensity * input.normal - lightDir); 
+    // Initialize the sum of colors.
+    colorSum = float4(0.0f, 0.0f, 0.0f, 1.0f);
 
-        // Determine the amount of specular light based on the reflection vector, viewing direction, and specular power.
-        specular = pow(saturate(dot(reflection, input.viewDirection)), specularPower);
+    // Add all of the light colors up.
+    for(i=0; i<NUM_LIGHTS; i++)
+    {
+        colorSum.r += colorArray[i].r;
+        colorSum.g += colorArray[i].g;
+        colorSum.b += colorArray[i].b;
     }
 
-    // Multiply the texture pixel and the final diffuse color to get the final pixel color result.
-    color = color * textureColor;
-
-    // Add the specular component last to the output color.
-    color = saturate(color + specular);
+    // Multiply the texture pixel by the combination of all four light colors to get the final result.
+    color = saturate(colorSum) * textureColor;
 
     return color;
 }