Split particle shader entry points

* Particle shaders now have start() and process()
* Particle collision happens between them.
* The RESTART property is kept, so porting an old shader is still possible.

This fixes the problem of particle collisions not functioning on the first particle frame.

1 files changed, 109 insertions, 105 deletions

diff --git a/servers/rendering/renderer_rd/shaders/particles.glsl b/servers/rendering/renderer_rd/shaders/particles.glsl
index c438352c05..3712220dc4 100644
--- a/servers/rendering/renderer_rd/shaders/particles.glsl
+++ b/servers/rendering/renderer_rd/shaders/particles.glsl
@@ -252,6 +252,115 @@ void main() {
 
 	/* Process physics if active */
 
+	if (params.sub_emitter_mode) {
+		if (!PARTICLE.is_active) {
+			int src_index = atomicAdd(src_particles.particle_count, -1) - 1;
+
+			if (src_index >= 0) {
+				PARTICLE.is_active = true;
+				restart = true;
+
+				if (bool(src_particles.data[src_index].flags & EMISSION_FLAG_HAS_POSITION)) {
+					PARTICLE.xform[3] = src_particles.data[src_index].xform[3];
+				} else {
+					PARTICLE.xform[3] = vec4(0, 0, 0, 1);
+					restart_position = true;
+				}
+				if (bool(src_particles.data[src_index].flags & EMISSION_FLAG_HAS_ROTATION_SCALE)) {
+					PARTICLE.xform[0] = src_particles.data[src_index].xform[0];
+					PARTICLE.xform[1] = src_particles.data[src_index].xform[1];
+					PARTICLE.xform[2] = src_particles.data[src_index].xform[2];
+				} else {
+					PARTICLE.xform[0] = vec4(1, 0, 0, 0);
+					PARTICLE.xform[1] = vec4(0, 1, 0, 0);
+					PARTICLE.xform[2] = vec4(0, 0, 1, 0);
+					restart_rotation_scale = true;
+				}
+				if (bool(src_particles.data[src_index].flags & EMISSION_FLAG_HAS_VELOCITY)) {
+					PARTICLE.velocity = src_particles.data[src_index].velocity;
+				} else {
+					PARTICLE.velocity = vec3(0);
+					restart_velocity = true;
+				}
+				if (bool(src_particles.data[src_index].flags & EMISSION_FLAG_HAS_COLOR)) {
+					PARTICLE.color = src_particles.data[src_index].color;
+				} else {
+					PARTICLE.color = vec4(1);
+					restart_color = true;
+				}
+
+				if (bool(src_particles.data[src_index].flags & EMISSION_FLAG_HAS_CUSTOM)) {
+					PARTICLE.custom = src_particles.data[src_index].custom;
+				} else {
+					PARTICLE.custom = vec4(0);
+					restart_custom = true;
+				}
+			}
+		}
+
+	} else if (FRAME.emitting) {
+		float restart_phase = float(index) / float(params.total_particles);
+
+		if (FRAME.randomness > 0.0) {
+			uint seed = FRAME.cycle;
+			if (restart_phase >= FRAME.system_phase) {
+				seed -= uint(1);
+			}
+			seed *= uint(params.total_particles);
+			seed += uint(index);
+			float random = float(hash(seed) % uint(65536)) / 65536.0;
+			restart_phase += FRAME.randomness * random * 1.0 / float(params.total_particles);
+		}
+
+		restart_phase *= (1.0 - FRAME.explosiveness);
+
+		if (FRAME.system_phase > FRAME.prev_system_phase) {
+			// restart_phase >= prev_system_phase is used so particles emit in the first frame they are processed
+
+			if (restart_phase >= FRAME.prev_system_phase && restart_phase < FRAME.system_phase) {
+				restart = true;
+				if (params.use_fractional_delta) {
+					local_delta = (FRAME.system_phase - restart_phase) * params.lifetime;
+				}
+			}
+
+		} else if (FRAME.delta > 0.0) {
+			if (restart_phase >= FRAME.prev_system_phase) {
+				restart = true;
+				if (params.use_fractional_delta) {
+					local_delta = (1.0 - restart_phase + FRAME.system_phase) * params.lifetime;
+				}
+
+			} else if (restart_phase < FRAME.system_phase) {
+				restart = true;
+				if (params.use_fractional_delta) {
+					local_delta = (FRAME.system_phase - restart_phase) * params.lifetime;
+				}
+			}
+		}
+
+		uint current_cycle = FRAME.cycle;
+
+		if (FRAME.system_phase < restart_phase) {
+			current_cycle -= uint(1);
+		}
+
+		uint particle_number = current_cycle * uint(params.total_particles) + particle;
+
+		if (restart) {
+			PARTICLE.is_active = FRAME.emitting;
+			restart_position = true;
+			restart_rotation_scale = true;
+			restart_velocity = true;
+			restart_color = true;
+			restart_custom = true;
+		}
+	}
+
+	if (restart && PARTICLE.is_active) {
+#CODE : START
+	}
+
 	if (PARTICLE.is_active) {
 		for (uint i = 0; i < FRAME.attractor_count; i++) {
 			vec3 dir;
@@ -430,111 +539,6 @@ void main() {
 		}
 	}
 
-	if (params.sub_emitter_mode) {
-		if (!PARTICLE.is_active) {
-			int src_index = atomicAdd(src_particles.particle_count, -1) - 1;
-
-			if (src_index >= 0) {
-				PARTICLE.is_active = true;
-				restart = true;
-
-				if (bool(src_particles.data[src_index].flags & EMISSION_FLAG_HAS_POSITION)) {
-					PARTICLE.xform[3] = src_particles.data[src_index].xform[3];
-				} else {
-					PARTICLE.xform[3] = vec4(0, 0, 0, 1);
-					restart_position = true;
-				}
-				if (bool(src_particles.data[src_index].flags & EMISSION_FLAG_HAS_ROTATION_SCALE)) {
-					PARTICLE.xform[0] = src_particles.data[src_index].xform[0];
-					PARTICLE.xform[1] = src_particles.data[src_index].xform[1];
-					PARTICLE.xform[2] = src_particles.data[src_index].xform[2];
-				} else {
-					PARTICLE.xform[0] = vec4(1, 0, 0, 0);
-					PARTICLE.xform[1] = vec4(0, 1, 0, 0);
-					PARTICLE.xform[2] = vec4(0, 0, 1, 0);
-					restart_rotation_scale = true;
-				}
-				if (bool(src_particles.data[src_index].flags & EMISSION_FLAG_HAS_VELOCITY)) {
-					PARTICLE.velocity = src_particles.data[src_index].velocity;
-				} else {
-					PARTICLE.velocity = vec3(0);
-					restart_velocity = true;
-				}
-				if (bool(src_particles.data[src_index].flags & EMISSION_FLAG_HAS_COLOR)) {
-					PARTICLE.color = src_particles.data[src_index].color;
-				} else {
-					PARTICLE.color = vec4(1);
-					restart_color = true;
-				}
-
-				if (bool(src_particles.data[src_index].flags & EMISSION_FLAG_HAS_CUSTOM)) {
-					PARTICLE.custom = src_particles.data[src_index].custom;
-				} else {
-					PARTICLE.custom = vec4(0);
-					restart_custom = true;
-				}
-			}
-		}
-
-	} else if (FRAME.emitting) {
-		float restart_phase = float(index) / float(params.total_particles);
-
-		if (FRAME.randomness > 0.0) {
-			uint seed = FRAME.cycle;
-			if (restart_phase >= FRAME.system_phase) {
-				seed -= uint(1);
-			}
-			seed *= uint(params.total_particles);
-			seed += uint(index);
-			float random = float(hash(seed) % uint(65536)) / 65536.0;
-			restart_phase += FRAME.randomness * random * 1.0 / float(params.total_particles);
-		}
-
-		restart_phase *= (1.0 - FRAME.explosiveness);
-
-		if (FRAME.system_phase > FRAME.prev_system_phase) {
-			// restart_phase >= prev_system_phase is used so particles emit in the first frame they are processed
-
-			if (restart_phase >= FRAME.prev_system_phase && restart_phase < FRAME.system_phase) {
-				restart = true;
-				if (params.use_fractional_delta) {
-					local_delta = (FRAME.system_phase - restart_phase) * params.lifetime;
-				}
-			}
-
-		} else if (FRAME.delta > 0.0) {
-			if (restart_phase >= FRAME.prev_system_phase) {
-				restart = true;
-				if (params.use_fractional_delta) {
-					local_delta = (1.0 - restart_phase + FRAME.system_phase) * params.lifetime;
-				}
-
-			} else if (restart_phase < FRAME.system_phase) {
-				restart = true;
-				if (params.use_fractional_delta) {
-					local_delta = (FRAME.system_phase - restart_phase) * params.lifetime;
-				}
-			}
-		}
-
-		uint current_cycle = FRAME.cycle;
-
-		if (FRAME.system_phase < restart_phase) {
-			current_cycle -= uint(1);
-		}
-
-		uint particle_number = current_cycle * uint(params.total_particles) + particle;
-
-		if (restart) {
-			PARTICLE.is_active = FRAME.emitting;
-			restart_position = true;
-			restart_rotation_scale = true;
-			restart_velocity = true;
-			restart_color = true;
-			restart_custom = true;
-		}
-	}
-
 	if (PARTICLE.is_active) {
 #CODE : PROCESS
 	}