DRW: Fix hair count being limited by recent refactor

This was making Autumn being half naked.

Issue was introduced by rBe72dc667c4d3

4 files changed, 28 insertions, 27 deletions

diff --git a/source/blender/draw/intern/draw_cache_impl_particles.c b/source/blender/draw/intern/draw_cache_impl_particles.c
index def425e3c7c..b23d5e0fb9c 100644
--- a/source/blender/draw/intern/draw_cache_impl_particles.c
+++ b/source/blender/draw/intern/draw_cache_impl_particles.c
@@ -185,7 +185,9 @@ static void particle_batch_cache_clear_hair(ParticleHairCache *hair_cache)
 	DRW_TEXTURE_FREE_SAFE(hair_cache->point_tex);
 
 	GPU_VERTBUF_DISCARD_SAFE(hair_cache->proc_strand_buf);
+	GPU_VERTBUF_DISCARD_SAFE(hair_cache->proc_strand_seg_buf);
 	DRW_TEXTURE_FREE_SAFE(hair_cache->strand_tex);
+	DRW_TEXTURE_FREE_SAFE(hair_cache->strand_seg_tex);
 
 	for (int i = 0; i < MAX_MTFACE; ++i) {
 		GPU_VERTBUF_DISCARD_SAFE(hair_cache->proc_uv_buf[i]);
@@ -769,7 +771,7 @@ static int particle_batch_cache_fill_strands_data(
         const ParticleSource particle_source,
         const int start_index,
         const int num_path_keys,
-        GPUVertBufRaw *data_step,
+        GPUVertBufRaw *data_step, GPUVertBufRaw *seg_step,
         float (***r_parent_uvs)[2], GPUVertBufRaw *uv_step, MTFace **mtfaces, int num_uv_layers,
         MCol ***r_parent_mcol, GPUVertBufRaw *col_step, MCol **mcols, int num_col_layers)
 {
@@ -793,12 +795,8 @@ static int particle_batch_cache_fill_strands_data(
 			continue;
 		}
 
-		/* XXX: We might need something more robust.
-		 * Adjust shader code accordingly. (see unpack_strand_data() ) */
-		BLI_assert((path->segments - 1) <= 0x3FF);
-
-		uint *seg_data = (uint *)GPU_vertbuf_raw_step(data_step);
-		*seg_data = (curr_point & 0x3FFFFF) | ((path->segments - 1) << 22);
+		*(uint *)GPU_vertbuf_raw_step(data_step) = curr_point;
+		*(ushort *)GPU_vertbuf_raw_step(seg_step) = path->segments;
 		curr_point += path->segments + 1;
 
 		if (psmd != NULL) {
@@ -883,7 +881,7 @@ static void particle_batch_cache_ensure_procedural_strand_data(
 		}
 	}
 
-	GPUVertBufRaw data_step;
+	GPUVertBufRaw data_step, seg_step;
 	GPUVertBufRaw uv_step[MAX_MTFACE];
 	GPUVertBufRaw col_step[MAX_MCOL];
 
@@ -895,6 +893,9 @@ static void particle_batch_cache_ensure_procedural_strand_data(
 	GPUVertFormat format_data = {0};
 	uint data_id = GPU_vertformat_attr_add(&format_data, "data", GPU_COMP_U32, 1, GPU_FETCH_INT);
 
+	GPUVertFormat format_seg = {0};
+	uint seg_id = GPU_vertformat_attr_add(&format_seg, "data", GPU_COMP_U16, 1, GPU_FETCH_INT);
+
 	GPUVertFormat format_uv = {0};
 	uint uv_id = GPU_vertformat_attr_add(&format_uv, "uv", GPU_COMP_F32, 2, GPU_FETCH_FLOAT);
 
@@ -909,6 +910,10 @@ static void particle_batch_cache_ensure_procedural_strand_data(
 	GPU_vertbuf_data_alloc(cache->proc_strand_buf, cache->strands_len);
 	GPU_vertbuf_attr_get_raw_data(cache->proc_strand_buf, data_id, &data_step);
 
+	cache->proc_strand_seg_buf = GPU_vertbuf_create_with_format(&format_seg);
+	GPU_vertbuf_data_alloc(cache->proc_strand_seg_buf, cache->strands_len);
+	GPU_vertbuf_attr_get_raw_data(cache->proc_strand_seg_buf, seg_id, &seg_step);
+
 	/* UV layers */
 	for (int i = 0; i < cache->num_uv_layers; i++) {
 		cache->proc_uv_buf[i] = GPU_vertbuf_create_with_format(&format_uv);
@@ -964,7 +969,7 @@ static void particle_batch_cache_ensure_procedural_strand_data(
 		particle_batch_cache_fill_strands_data(
 		        psys, psmd, edit->pathcache, PARTICLE_SOURCE_PARENT,
 		        0, edit->totcached,
-		        &data_step,
+		        &data_step, &seg_step,
 		        &parent_uvs, uv_step, (MTFace **)mtfaces, cache->num_uv_layers,
 		        &parent_mcol, col_step, (MCol **)mcols, cache->num_col_layers);
 	}
@@ -976,7 +981,7 @@ static void particle_batch_cache_ensure_procedural_strand_data(
 			curr_point = particle_batch_cache_fill_strands_data(
 			        psys, psmd, psys->pathcache, PARTICLE_SOURCE_PARENT,
 			        0, psys->totpart,
-			        &data_step,
+			        &data_step, &seg_step,
 			        &parent_uvs, uv_step, (MTFace **)mtfaces, cache->num_uv_layers,
 			        &parent_mcol, col_step, (MCol **)mcols, cache->num_col_layers);
 		}
@@ -985,7 +990,7 @@ static void particle_batch_cache_ensure_procedural_strand_data(
 			curr_point = particle_batch_cache_fill_strands_data(
 			        psys, psmd, psys->childcache, PARTICLE_SOURCE_CHILDREN,
 			        curr_point, child_count,
-			        &data_step,
+			        &data_step, &seg_step,
 			        &parent_uvs, uv_step, (MTFace **)mtfaces, cache->num_uv_layers,
 			        &parent_mcol, col_step, (MCol **)mcols, cache->num_col_layers);
 		}
@@ -1009,6 +1014,9 @@ static void particle_batch_cache_ensure_procedural_strand_data(
 	GPU_vertbuf_use(cache->proc_strand_buf);
 	cache->strand_tex = GPU_texture_create_from_vertbuf(cache->proc_strand_buf);
 
+	GPU_vertbuf_use(cache->proc_strand_seg_buf);
+	cache->strand_seg_tex = GPU_texture_create_from_vertbuf(cache->proc_strand_seg_buf);
+
 	for (int i = 0; i < cache->num_uv_layers; i++) {
 		GPU_vertbuf_use(cache->proc_uv_buf[i]);
 		cache->uv_tex[i] = GPU_texture_create_from_vertbuf(cache->proc_uv_buf[i]);
diff --git a/source/blender/draw/intern/draw_hair.c b/source/blender/draw/intern/draw_hair.c
index 1d0fb5cb2a8..6c1e44ac8e7 100644
--- a/source/blender/draw/intern/draw_hair.c
+++ b/source/blender/draw/intern/draw_hair.c
@@ -212,6 +212,7 @@ static DRWShadingGroup *drw_shgroup_create_hair_procedural_ex(
 
 		DRW_shgroup_uniform_texture(tf_shgrp, "hairPointBuffer", hair_cache->point_tex);
 		DRW_shgroup_uniform_texture(tf_shgrp, "hairStrandBuffer", hair_cache->strand_tex);
+		DRW_shgroup_uniform_texture(tf_shgrp, "hairStrandSegBuffer", hair_cache->strand_seg_tex);
 		DRW_shgroup_uniform_int(tf_shgrp, "hairStrandsRes", &hair_cache->final[subdiv].strands_res, 1);
 		DRW_shgroup_call_procedural_points_add(tf_shgrp, final_points_len, NULL);
 	}
diff --git a/source/blender/draw/intern/draw_hair_private.h b/source/blender/draw/intern/draw_hair_private.h
index c77f236e066..8f7cb1fe949 100644
--- a/source/blender/draw/intern/draw_hair_private.h
+++ b/source/blender/draw/intern/draw_hair_private.h
@@ -54,9 +54,13 @@ typedef struct ParticleHairCache {
 	GPUVertBuf *proc_point_buf; /* Input control points */
 	GPUTexture *point_tex;
 
-	GPUVertBuf *proc_strand_buf; /* Infos of control points strands (segment count and base index) */
+	/** Infos of control points strands (segment count and base index) */
+	GPUVertBuf *proc_strand_buf;
 	GPUTexture *strand_tex;
 
+	GPUVertBuf *proc_strand_seg_buf;
+	GPUTexture *strand_seg_tex;
+
 	GPUVertBuf *proc_uv_buf[MAX_MTFACE];
 	GPUTexture *uv_tex[MAX_MTFACE];
 	char uv_layer_names[MAX_MTFACE][MAX_LAYER_NAME_CT][MAX_LAYER_NAME_LEN];
diff --git a/source/blender/draw/modes/shaders/common_hair_lib.glsl b/source/blender/draw/modes/shaders/common_hair_lib.glsl
index 9cda44c8f42..14df29f2e94 100644
--- a/source/blender/draw/modes/shaders/common_hair_lib.glsl
+++ b/source/blender/draw/modes/shaders/common_hair_lib.glsl
@@ -35,22 +35,12 @@ uniform samplerBuffer hairPointBuffer; /* RGBA32F */
 
 /* -- Per strands data -- */
 uniform usamplerBuffer hairStrandBuffer; /* R32UI */
+uniform usamplerBuffer hairStrandSegBuffer; /* R16UI */
 
 /* Not used, use one buffer per uv layer */
 //uniform samplerBuffer hairUVBuffer; /* RG32F */
 //uniform samplerBuffer hairColBuffer; /* RGBA16 linear color */
 
-void unpack_strand_data(uint data, out int strand_offset, out int strand_segments)
-{
-#if 0 /* Pack point count */
-	// strand_offset = (data & 0x1FFFFFFFu);
-	// strand_segments = 1u << (data >> 29u); /* We only need 3 bits to store subdivision level. */
-#else
-	strand_offset = int(data & 0x003FFFFFu);
-	strand_segments = int(data >> 22u) + 1;
-#endif
-}
-
 /* -- Subdivision stage -- */
 /**
  * We use a transform feedback to preprocess the strands and add more subdivision to it.
@@ -76,10 +66,8 @@ void hair_get_interp_attrs(out vec4 data0, out vec4 data1, out vec4 data2, out v
 	float local_time = float(gl_VertexID % hairStrandsRes) / float(hairStrandsRes - 1);
 
 	int hair_id = gl_VertexID / hairStrandsRes;
-	uint strand_data = texelFetch(hairStrandBuffer, hair_id).x;
-
-	int strand_offset, strand_segments;
-	unpack_strand_data(strand_data, strand_offset, strand_segments);
+	int strand_offset = int(texelFetch(hairStrandBuffer, hair_id).x);
+	int strand_segments = int(texelFetch(hairStrandSegBuffer, hair_id).x);
 
 	int id = hair_get_base_id(local_time, strand_segments, interp_time);