Support for textures in vertex painting.

Developer notes: this commit does painting in sRGB space. Since colours
are stored im byte per component formats, expect this to have the usual
dark fringing issues. Speed wise vertex paint could use some
optimization, for instance we could store the screen space vertex
positions on initialization like we do for texture painting, but this is
for another time. Also noticed that vertex painting suffers from the
subsurf + mirror issue too :/

Apart from that it's quite exciting how easy it is to add support for
texturing now that proper abstractions for texture sampling have been
done :)

1 files changed, 33 insertions, 8 deletions

diff --git a/source/blender/editors/sculpt_paint/paint_vertex.c b/source/blender/editors/sculpt_paint/paint_vertex.c
index 2705ea3b4f8..2dbbe9f1b81 100644
--- a/source/blender/editors/sculpt_paint/paint_vertex.c
+++ b/source/blender/editors/sculpt_paint/paint_vertex.c
@@ -43,6 +43,7 @@
 
 #include "BLI_blenlib.h"
 #include "BLI_math.h"
+#include "BLI_math_color.h"
 #include "BLI_memarena.h"
 #include "BLI_utildefines.h"
 #include "BLI_ghash.h"
@@ -854,8 +855,8 @@ static int sample_backbuf_area(ViewContext *vc, int *indexar, int totface, int x
 }
 
 /* whats _dl mean? */
-static float calc_vp_strength_dl(VPaint *vp, ViewContext *vc, const float co[3],
-                                 const float mval[2], const float brush_size_pressure)
+static float calc_vp_strength_col_dl(VPaint *vp, ViewContext *vc, const float co[3],
+                                 const float mval[2], const float brush_size_pressure, float rgba[4])
 {
 	float vertco[2];
 
@@ -871,19 +872,26 @@ static float calc_vp_strength_dl(VPaint *vp, ViewContext *vc, const float co[3],
 		if (dist_squared <= brush_size_pressure * brush_size_pressure) {
 			Brush *brush = paint_brush(&vp->paint);
 			const float dist = sqrtf(dist_squared);
+			if (brush->mtex.tex) {
+				if (brush->mtex.brush_map_mode == MTEX_MAP_MODE_3D)
+					BKE_brush_sample_tex_3D(vc->scene, brush, co, rgba, 0, NULL);
+				else
+					BKE_brush_sample_tex_3D(vc->scene, brush, vertco, rgba, 0, NULL);
+			}
 			return BKE_brush_curve_strength_clamp(brush, dist, brush_size_pressure);
 		}
 	}
 
+	zero_v4(rgba);
 	return 0.0f;
 }
 
 static float calc_vp_alpha_dl(VPaint *vp, ViewContext *vc,
                               float vpimat[3][3], const DMCoNo *v_co_no,
                               const float mval[2],
-                              const float brush_size_pressure, const float brush_alpha_pressure)
+                              const float brush_size_pressure, const float brush_alpha_pressure, float rgba[4])
 {
-	float strength = calc_vp_strength_dl(vp, vc, v_co_no->co, mval, brush_size_pressure);
+	float strength = calc_vp_strength_col_dl(vp, vc, v_co_no->co, mval, brush_size_pressure, rgba);
 
 	if (strength > 0.0f) {
 		float alpha = brush_alpha_pressure * strength;
@@ -2307,7 +2315,7 @@ static void wpaint_stroke_update_step(bContext *C, struct PaintStroke *stroke, P
 #define WP_BLUR_ACCUM(v_idx_var)  \
 	{ \
 		const unsigned int vidx = v_idx_var; \
-		const float fac = calc_vp_strength_dl(wp, vc, wpd->vertexcosnos[vidx].co, mval, brush_size_pressure); \
+		const float fac = calc_vp_strength_col_dl(wp, vc, wpd->vertexcosnos[vidx].co, mval, brush_size_pressure, NULL); \
 		if (fac > 0.0f) { \
 			MDeformWeight *dw = dw_func(&me->dvert[vidx], wpi.vgroup_active); \
 			paintweight += dw ? (dw->weight * fac) : 0.0f; \
@@ -2378,7 +2386,7 @@ static void wpaint_stroke_update_step(bContext *C, struct PaintStroke *stroke, P
 		unsigned int vidx = v_idx_var; \
 		if (me->dvert[vidx].flag) { \
 			alpha = calc_vp_alpha_dl(wp, vc, wpd->wpimat, &wpd->vertexcosnos[vidx], \
-			                         mval, brush_size_pressure, brush_alpha_pressure); \
+			                         mval, brush_size_pressure, brush_alpha_pressure, NULL); \
 			if (alpha) { \
 				do_weight_paint_vertex(wp, ob, &wpi, vidx, alpha, paintweight); \
 			} \
@@ -2662,6 +2670,8 @@ typedef struct VPaintData {
 	/* mpoly -> mface mapping */
 	MemArena *polyfacemap_arena;
 	ListBase *polyfacemap;
+
+	bool is_texbrush;
 } VPaintData;
 
 static void vpaint_build_poly_facemap(struct VPaintData *vd, Mesh *me)
@@ -2698,6 +2708,7 @@ static int vpaint_stroke_test_start(bContext *C, struct wmOperator *op, const fl
 	ToolSettings *ts = CTX_data_tool_settings(C);
 	struct PaintStroke *stroke = op->customdata;
 	VPaint *vp = ts->vpaint;
+	Brush *brush = paint_brush(&vp->paint);
 	struct VPaintData *vpd;
 	Object *ob = CTX_data_active_object(C);
 	Mesh *me;
@@ -2727,6 +2738,8 @@ static int vpaint_stroke_test_start(bContext *C, struct wmOperator *op, const fl
 	vpd->indexar = get_indexarray(me);
 	vpd->paintcol = vpaint_get_current_col(vp);
 
+	vpd->is_texbrush = !(brush->vertexpaint_tool == PAINT_BLEND_BLUR) &&
+	                   brush->mtex.tex;
 
 	/* are we painting onto a modified mesh?,
 	 * if not we can skip face map trickyness */
@@ -2803,12 +2816,24 @@ static void vpaint_paint_poly(VPaint *vp, VPaintData *vpd, Mesh *me,
 
 	ml = me->mloop + mpoly->loopstart;
 	for (i = 0; i < mpoly->totloop; i++, ml++) {
+		float rgba[4];
+		unsigned int paintcol;
 		alpha = calc_vp_alpha_dl(vp, vc, vpd->vpimat,
 		                         &vpd->vertexcosnos[ml->v], mval,
-		                         brush_size_pressure, brush_alpha_pressure);
+		                         brush_size_pressure, brush_alpha_pressure, rgba);
+
+		if (vpd->is_texbrush) {
+			float rgba_br[3];
+			rgb_uchar_to_float(rgba_br, (const unsigned char *)&vpd->paintcol);
+			mul_v3_v3(rgba_br, rgba);
+			rgb_float_to_uchar((unsigned char *)&paintcol, rgba_br);
+		}
+		else
+			paintcol = vpd->paintcol;
+
 		if (alpha > 0.0f) {
 			const int alpha_i = (int)(alpha * 255.0f);
-			lcol[i] = vpaint_blend(vp, lcol[i], lcolorig[i], vpd->paintcol, alpha_i, brush_alpha_pressure_i);
+			lcol[i] = vpaint_blend(vp, lcol[i], lcolorig[i], paintcol, alpha_i, brush_alpha_pressure_i);
 		}
 	}