Cycles: restore Particle Info Index for now, keep it next to Random.

It seems to be useful still in cases where the particle are distributed in
a particular order or pattern, to colorize them along with that. This isn't
really well defined, but might as well avoid breaking backwards compatibility
for now.

4 files changed, 11 insertions, 8 deletions

diff --git a/source/blender/gpu/GPU_material.h b/source/blender/gpu/GPU_material.h
index dbfcd4d1ea4..e229afd3323 100644
--- a/source/blender/gpu/GPU_material.h
+++ b/source/blender/gpu/GPU_material.h
@@ -344,10 +344,9 @@ void GPU_zenith_update_color(float color[3]);
 struct GPUParticleInfo
 {
 	float scalprops[4];
-	float location[3];
+	float location[4];
 	float velocity[3];
 	float angular_velocity[3];
-	int random_id;
 };
 
 #ifdef WITH_OPENSUBDIV
diff --git a/source/blender/gpu/intern/gpu_draw.c b/source/blender/gpu/intern/gpu_draw.c
index d7e744951c4..61d57dee092 100644
--- a/source/blender/gpu/intern/gpu_draw.c
+++ b/source/blender/gpu/intern/gpu_draw.c
@@ -1884,12 +1884,14 @@ static int gpu_get_particle_info(GPUParticleInfo *pi)
 		if (ind >= 0) {
 			ParticleData *p = &dob->particle_system->particles[ind];
 
-			pi->scalprops[0] = BLI_hash_int_01(ind);
+			pi->scalprops[0] = ind;
 			pi->scalprops[1] = GMS.gscene->r.cfra - p->time;
 			pi->scalprops[2] = p->lifetime;
 			pi->scalprops[3] = p->size;
 
 			copy_v3_v3(pi->location, p->state.co);
+			pi->location[3] = BLI_hash_int_01(ind);
+
 			copy_v3_v3(pi->velocity, p->state.vel);
 			copy_v3_v3(pi->angular_velocity, p->state.ave);
 			return 1;
diff --git a/source/blender/gpu/intern/gpu_material.c b/source/blender/gpu/intern/gpu_material.c
index 33eac16dadf..edb6c9a29f9 100644
--- a/source/blender/gpu/intern/gpu_material.c
+++ b/source/blender/gpu/intern/gpu_material.c
@@ -452,7 +452,7 @@ void GPU_material_bind_uniforms(
 			GPU_shader_uniform_vector(shader, material->partscalarpropsloc, 4, 1, pi->scalprops);
 		}
 		if (material->builtins & GPU_PARTICLE_LOCATION) {
-			GPU_shader_uniform_vector(shader, material->partcoloc, 3, 1, pi->location);
+			GPU_shader_uniform_vector(shader, material->partcoloc, 4, 1, pi->location);
 		}
 		if (material->builtins & GPU_PARTICLE_VELOCITY) {
 			GPU_shader_uniform_vector(shader, material->partvel, 3, 1, pi->velocity);
diff --git a/source/blender/gpu/shaders/gpu_shader_material.glsl b/source/blender/gpu/shaders/gpu_shader_material.glsl
index 5fe14e76a90..1f5ffbdcc7e 100644
--- a/source/blender/gpu/shaders/gpu_shader_material.glsl
+++ b/source/blender/gpu/shaders/gpu_shader_material.glsl
@@ -189,16 +189,18 @@ void geom(
 }
 
 void particle_info(
-        vec4 sprops, vec3 loc, vec3 vel, vec3 avel,
-        out float random, out float age, out float life_time, out vec3 location,
+        vec4 sprops, vec4 loc, vec3 vel, vec3 avel,
+        out float index, out float random, out float age,
+        out float life_time, out vec3 location,
         out float size, out vec3 velocity, out vec3 angular_velocity)
 {
-	random = sprops.x;
+	index = sprops.x;
+	random = loc.w;
 	age = sprops.y;
 	life_time = sprops.z;
 	size = sprops.w;
 
-	location = loc;
+	location = loc.xyz;
 	velocity = vel;
 	angular_velocity = avel;
 }