[Bf-blender-cvs] [16f8444] master: Fix T47147: small particles incorrectly rendered as large particles (particle size influenced by texture).

[Bastien Montagne]

Commit: 16f8444d9d64967331e1a386ecc676b464869428
Author: Bastien Montagne
Date:   Mon Jan 11 17:01:09 2016 +0100
Branches: master
https://developer.blender.org/rB16f8444d9d64967331e1a386ecc676b464869428

Fix T47147: small particles incorrectly rendered as large particles (particle size influenced by texture).

In fact, code would behave strangely here with any negative value, applying a 'wrapped positive clamping'
(comes from original 2.5 commit feature, rBfafbd9d71b95776d1c7583476de74fccefab7f10)...

This commit is conservative - it keeps same behavior for all particle properties affected by textures,
except for size and length, where we apply a real [0, 1] clamping.

Easy to change in future in case new odd cases popup.

===================================================================

M	source/blender/blenkernel/intern/particle.c

===================================================================

diff --git a/source/blender/blenkernel/intern/particle.c b/source/blender/blenkernel/intern/particle.c
index e8fcb5c..5a6f1da 100644
--- a/source/blender/blenkernel/intern/particle.c
+++ b/source/blender/blenkernel/intern/particle.c
@@ -3427,6 +3427,11 @@ static int get_particle_uv(DerivedMesh *dm, ParticleData *pa, int face_index, co
 
 #define CLAMP_PARTICLE_TEXTURE_POS(type, pvalue)                              \
 	if (event & type) {                                                       \
+		CLAMP(pvalue, 0.0f, 1.0f);                                            \
+	} (void)0
+
+#define CLAMP_WARP_PARTICLE_TEXTURE_POS(type, pvalue)                              \
+	if (event & type) {                                                       \
 		if (pvalue < 0.0f)                                                    \
 			pvalue = 1.0f + pvalue;                                           \
 		CLAMP(pvalue, 0.0f, 1.0f);                                            \
@@ -3498,11 +3503,11 @@ static void get_cpa_texture(DerivedMesh *dm, ParticleSystem *psys, ParticleSetti
 	}
 
 	CLAMP_PARTICLE_TEXTURE_POS(PAMAP_LENGTH, ptex->length);
-	CLAMP_PARTICLE_TEXTURE_POS(PAMAP_CLUMP, ptex->clump);
-	CLAMP_PARTICLE_TEXTURE_POS(PAMAP_KINK_AMP, ptex->kink_amp);
-	CLAMP_PARTICLE_TEXTURE_POS(PAMAP_KINK_FREQ, ptex->kink_freq);
-	CLAMP_PARTICLE_TEXTURE_POS(PAMAP_ROUGH, ptex->rough1);
-	CLAMP_PARTICLE_TEXTURE_POS(PAMAP_DENS, ptex->exist);
+	CLAMP_WARP_PARTICLE_TEXTURE_POS(PAMAP_CLUMP, ptex->clump);
+	CLAMP_WARP_PARTICLE_TEXTURE_POS(PAMAP_KINK_AMP, ptex->kink_amp);
+	CLAMP_WARP_PARTICLE_TEXTURE_POS(PAMAP_KINK_FREQ, ptex->kink_freq);
+	CLAMP_WARP_PARTICLE_TEXTURE_POS(PAMAP_ROUGH, ptex->rough1);
+	CLAMP_WARP_PARTICLE_TEXTURE_POS(PAMAP_DENS, ptex->exist);
 }
 void psys_get_texture(ParticleSimulationData *sim, ParticleData *pa, ParticleTexture *ptex, int event, float cfra)
 {
@@ -3592,14 +3597,14 @@ void psys_get_texture(ParticleSimulationData *sim, ParticleData *pa, ParticleTex
 		}
 	}
 
-	CLAMP_PARTICLE_TEXTURE_POS(PAMAP_TIME, ptex->time);
-	CLAMP_PARTICLE_TEXTURE_POS(PAMAP_LIFE, ptex->life);
-	CLAMP_PARTICLE_TEXTURE_POS(PAMAP_DENS, ptex->exist);
+	CLAMP_WARP_PARTICLE_TEXTURE_POS(PAMAP_TIME, ptex->time);
+	CLAMP_WARP_PARTICLE_TEXTURE_POS(PAMAP_LIFE, ptex->life);
+	CLAMP_WARP_PARTICLE_TEXTURE_POS(PAMAP_DENS, ptex->exist);
 	CLAMP_PARTICLE_TEXTURE_POS(PAMAP_SIZE, ptex->size);
 	CLAMP_PARTICLE_TEXTURE_POSNEG(PAMAP_IVEL, ptex->ivel);
 	CLAMP_PARTICLE_TEXTURE_POSNEG(PAMAP_FIELD, ptex->field);
 	CLAMP_PARTICLE_TEXTURE_POSNEG(PAMAP_GRAVITY, ptex->gravity);
-	CLAMP_PARTICLE_TEXTURE_POS(PAMAP_DAMP, ptex->damp);
+	CLAMP_WARP_PARTICLE_TEXTURE_POS(PAMAP_DAMP, ptex->damp);
 	CLAMP_PARTICLE_TEXTURE_POS(PAMAP_LENGTH, ptex->length);
 }
 /************************************************/