Fix cycles issue with mapping node rotation and scale order. When using both

scale and rotation in mapping node, there would be shearing, and the only way
to avoid that was to add 2 mapping nodes. This is because to transform the
texture, the inverse transform needs to be done on the texture coordinate

Now the mapping node has Texture/Point/Vector/Normal types to transform the
vector for a particular purpose. Point is the existing behavior, Texture is
the new default that behaves more like you might expect.

2 files changed, 50 insertions, 17 deletions

diff --git a/source/blender/blenkernel/BKE_texture.h b/source/blender/blenkernel/BKE_texture.h
index ac0d507003e..2a00dee2a3f 100644
--- a/source/blender/blenkernel/BKE_texture.h
+++ b/source/blender/blenkernel/BKE_texture.h
@@ -101,8 +101,8 @@ void set_current_particle_texture(struct ParticleSettings *part, struct Tex *tex
 
 int has_current_material_texture(struct Material *ma);
 
-struct TexMapping *add_tex_mapping(void);
-void default_tex_mapping(struct TexMapping *texmap);
+struct TexMapping *add_tex_mapping(int type);
+void default_tex_mapping(struct TexMapping *texmap, int type);
 void init_tex_mapping(struct TexMapping *texmap);
 
 struct ColorMapping *add_color_mapping(void);
diff --git a/source/blender/blenkernel/intern/texture.c b/source/blender/blenkernel/intern/texture.c
index e2b7358525a..d98a6cbe0cc 100644
--- a/source/blender/blenkernel/intern/texture.c
+++ b/source/blender/blenkernel/intern/texture.c
@@ -71,16 +71,16 @@
 
 /* ****************** Mapping ******************* */
 
-TexMapping *add_tex_mapping(void)
+TexMapping *add_tex_mapping(int type)
 {
 	TexMapping *texmap = MEM_callocN(sizeof(TexMapping), "TexMapping");
 	
-	default_tex_mapping(texmap);
+	default_tex_mapping(texmap, type);
 	
 	return texmap;
 }
 
-void default_tex_mapping(TexMapping *texmap)
+void default_tex_mapping(TexMapping *texmap, int type)
 {
 	memset(texmap, 0, sizeof(TexMapping));
 
@@ -92,11 +92,12 @@ void default_tex_mapping(TexMapping *texmap)
 	texmap->projy = PROJ_Y;
 	texmap->projz = PROJ_Z;
 	texmap->mapping = MTEX_FLAT;
+	texmap->type = type;
 }
 
 void init_tex_mapping(TexMapping *texmap)
 {
-	float smat[3][3], rmat[3][3], mat[3][3], proj[3][3];
+	float smat[4][4], rmat[4][4], tmat[4][4], proj[4][4], size[3];
 
 	if (texmap->projx == PROJ_X && texmap->projy == PROJ_Y && texmap->projz == PROJ_Z &&
 	    is_zero_v3(texmap->loc) && is_zero_v3(texmap->rot) && is_one_v3(texmap->size))
@@ -107,7 +108,8 @@ void init_tex_mapping(TexMapping *texmap)
 	}
 	else {
 		/* axis projection */
-		zero_m3(proj);
+		zero_m4(proj);
+		proj[3][3] = 1.0f;
 
 		if (texmap->projx != PROJ_N)
 			proj[texmap->projx - 1][0] = 1.0f;
@@ -117,19 +119,50 @@ void init_tex_mapping(TexMapping *texmap)
 			proj[texmap->projz - 1][2] = 1.0f;
 
 		/* scale */
-		size_to_mat3(smat, texmap->size);
+		copy_v3_v3(size, texmap->size);
+
+		if (ELEM(texmap->type, TEXMAP_TYPE_TEXTURE, TEXMAP_TYPE_NORMAL)) {
+			/* keep matrix invertible */
+			if(fabsf(size[0]) < 1e-5f)
+				size[0] = signf(size[0])*1e-5f;
+			if(fabsf(size[1]) < 1e-5f)
+				size[1] = signf(size[1])*1e-5f;
+			if(fabsf(size[2]) < 1e-5f)
+				size[2] = signf(size[2])*1e-5f;
+		}
 		
+		size_to_mat4(smat, texmap->size);
+
 		/* rotation */
-		/* TexMapping rotation are now in radians. */
-		eul_to_mat3(rmat, texmap->rot);
-		
-		/* compose it all */
-		mul_m3_m3m3(mat, rmat, smat);
-		mul_m3_m3m3(mat, proj, mat);
-		
+		eul_to_mat4(rmat, texmap->rot);
+
 		/* translation */
-		copy_m4_m3(texmap->mat, mat);
-		copy_v3_v3(texmap->mat[3], texmap->loc);
+		unit_m4(tmat);
+		copy_v3_v3(tmat[3], texmap->loc);
+
+		if (texmap->type == TEXMAP_TYPE_TEXTURE) {
+			/* to transform a texture, the inverse transform needs
+			 * to be applied to the texture coordinate */
+			mul_serie_m4(texmap->mat, tmat, rmat, smat, 0, 0, 0, 0, 0);
+			invert_m4(texmap->mat);
+		}
+		else if (texmap->type == TEXMAP_TYPE_POINT) {
+			/* forward transform */
+			mul_serie_m4(texmap->mat, tmat, rmat, smat, 0, 0, 0, 0, 0);
+		}
+		else if (texmap->type == TEXMAP_TYPE_VECTOR) {
+			/* no translation for vectors */
+			mul_m4_m4m4(texmap->mat, rmat, smat);
+		}
+		else if (texmap->type == TEXMAP_TYPE_NORMAL) {
+			/* no translation for normals, and inverse transpose */
+			mul_m4_m4m4(texmap->mat, rmat, smat);
+			invert_m4(texmap->mat);
+			transpose_m4(texmap->mat);
+		}
+
+		/* projection last */
+		mul_m4_m4m4(texmap->mat, texmap->mat, proj);
 
 		texmap->flag &= ~TEXMAP_UNIT_MATRIX;
 	}