feat: Add support to multiple lights using the uniform array [flame3d][WIP]

packages/flame_3d/lib/src/resources/light/light.dart

@@ -23,8 +23,8 @@ class Light extends Resource<void> {
   void createResource() {}
 
   void apply(int index, Shader shader) {
-    shader.setVector3('Light$index.position', transform.position);
-    shader.setColor('Light$index.color', source.color);
-    shader.setFloat('Light$index.intensity', source.intensity);
+    shader.setVector3('Light[$index].position', transform.position);
+    shader.setColor('Light[$index].color', source.color);
+    shader.setFloat('Light[$index].intensity', source.intensity);
   }
 }

packages/flame_3d/lib/src/resources/light/lighting_info.dart

@@ -16,9 +16,8 @@ class LightingInfo {
   void _applyPointLights(Shader shader) {
     final pointLights = lights.where((e) => e.source is PointLight);
     final numLights = pointLights.length;
-    if (numLights > 3) {
-      // temporary, until we support dynamic arrays
-      throw Exception('At most 3 point lights are allowed');
+    if (numLights > maxLights) {
+      throw Exception('At most $maxLights point lights are allowed');
     }
 
     shader.setUint('LightsInfo.numLights', numLights);
@@ -39,10 +38,13 @@ class LightingInfo {
   }
 
   static List<UniformSlot> shaderSlots = [
+    UniformSlot.array('Light', {'position', 'color', 'intensity'}),
     UniformSlot.value('AmbientLight', {'color', 'intensity'}),
     UniformSlot.value('LightsInfo', {'numLights'}),
-    UniformSlot.value('Light0', {'position', 'color', 'intensity'}),
-    UniformSlot.value('Light1', {'position', 'color', 'intensity'}),
-    UniformSlot.value('Light2', {'position', 'color', 'intensity'}),
   ];
+
+  /// The maximum number of point lights supported by the shader.
+  /// Since we use fixed-length arrays in the shader, we cannot support an
+  /// arbitrary number of lights.
+  static const maxLights = 8;
 }

packages/flame_3d/shaders/spatial_material.frag

@@ -2,7 +2,7 @@
 
 // implementation based on https://learnopengl.com/PBR/Lighting
 
-// #define NUM_LIGHTS 8
+#define MAX_LIGHTS 8
 #define PI 3.14159265359
 #define EPSILON 0.0001
 
@@ -23,7 +23,13 @@ uniform Material {
   float roughness;
 } material;
 
-// light info
+// lighting info
+
+uniform Light {
+  vec3 position;
+  vec4 color;
+  float intensity;
+} lights[MAX_LIGHTS];
 
 uniform AmbientLight {
   vec4 color;
@@ -34,30 +40,6 @@ uniform LightsInfo {
   uint numLights;
 } lightsInfo;
 
-// uniform Light {
-//   vec3 position;
-//   vec3 color;
-//   float intensity;
-// } lights[NUM_LIGHTS];
-
-uniform Light0 {
-  vec3 position;
-  vec4 color;
-  float intensity;
-} light0;
-
-uniform Light1 {
-  vec3 position;
-  vec4 color;
-  float intensity;
-} light1;
-
-uniform Light2 {
-  vec3 position;
-  vec4 color;
-  float intensity;
-} light2;
-
 // camera info
 
 uniform Camera {
@@ -150,28 +132,12 @@ void main() {
 
   vec3 lo = vec3(0.0);
 
-  if (lightsInfo.numLights > 0) {
-    vec3 light0Pos = light0.position;
-    vec3 light0Color = light0.color.rgb;
-    float light0Intensity = light0.intensity;
-
-    lo += processLight(light0Pos, light0Color, light0Intensity, baseColor, normal, viewDir, diffuse);
-  }
-
-  if (lightsInfo.numLights > 1) {
-    vec3 light1Pos = light1.position;
-    vec3 light1Color = light1.color.rgb;
-    float light1Intensity = light1.intensity;
-
-    lo += processLight(light1Pos, light1Color, light1Intensity, baseColor, normal, viewDir, diffuse);
-  }
-
-  if (lightsInfo.numLights > 2) {
-    vec3 light2Pos = light2.position;
-    vec3 light2Color = light2.color.rgb;
-    float light2Intensity = light2.intensity;
+  for (uint i = 0; i < lightsInfo.numLights; i++) {
+    vec3 lightPos = lights[i].position.xyz;
+    vec3 lightColor = lights[i].color.rgb;
+    float lightIntensity = lights[i].intensity;
 
-    lo += processLight(light2Pos, light2Color, light2Intensity, baseColor, normal, viewDir, diffuse);
+    lo += processLight(lightPos, lightColor, lightIntensity, baseColor, normal, viewDir, diffuse);
   }
 
   vec3 color = ambient + lo;
@@ -180,4 +146,4 @@ void main() {
   color = pow(color, vec3(1.0 / 2.2));
 
   outColor = vec4(color, 1.0);
-}
+}