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-rw-r--r--include/shadow.h3
-rw-r--r--shaders/model.frag.slang163
-rw-r--r--src/model.c27
-rw-r--r--src/shadow.c17
4 files changed, 185 insertions, 25 deletions
diff --git a/include/shadow.h b/include/shadow.h
index 0087ef4..b054418 100644
--- a/include/shadow.h
+++ b/include/shadow.h
@@ -27,11 +27,14 @@
extern SDL_GPUTexture *ta_shadow_texture;
extern SDL_GPUSampler *ta_shadow_sampler;
+extern SDL_GPUSampler *ta_shadow_depth_sampler;
extern float ta_shadow_light_direction[TA_SHADOW_DIMENSION];
extern float ta_shadow_normal_offset;
extern float ta_shadow_minimum_bias;
extern float ta_shadow_maximum_bias;
extern float ta_shadow_strength;
+extern float ta_shadow_light_size;
+extern float ta_shadow_penumbra_scale;
void ta_shadow_init(void);
void ta_shadow_get_light_view_projection(float *matrix);
diff --git a/shaders/model.frag.slang b/shaders/model.frag.slang
index ac12d0e..c8e9f90 100644
--- a/shaders/model.frag.slang
+++ b/shaders/model.frag.slang
@@ -22,17 +22,17 @@ struct light_uniforms {
float shadow_minimum_bias;
float shadow_maximum_bias;
float shadow_strength;
- float padding;
+ float shadow_penumbra_scale;
};
[[vk::binding(0, 3)]]
ConstantBuffer<light_uniforms> light : register(b0, space3);
[[vk::binding(0, 2)]]
-Texture2D<float> shadow_map : register(t0, space2);
+Sampler2DShadow shadow_map : register(t0, space2);
[[vk::binding(1, 2)]]
-SamplerComparisonState shadow_sampler : register(s0, space2);
+Sampler2D<float> shadow_depth_map : register(t1, space2);
struct FSInput {
float3 normal : TEXCOORD0;
@@ -49,7 +49,142 @@ static const float ambient_strength = 0.22;
static const float diffuse_strength = 0.78;
static const float specular_strength = 0.6;
static const float shininess = 32.0;
-static const int shadow_pcf_radius = 1;
+
+static const int shadow_blocker_sample_count = 32;
+static const int shadow_pcf_sample_count = 64;
+static const float shadow_maximum_search_uv = 0.02;
+static const float shadow_minimum_filter_texels = 1.5;
+static const float shadow_maximum_filter_uv = 0.02;
+
+static const float2 blocker_search_disk[shadow_blocker_sample_count] = {
+ float2( 0.44011213, -0.38478364),
+ float2(-0.93881893, 0.28433844),
+ float2( 0.29851448, 0.91473036),
+ float2(-0.56853028, -0.74873636),
+ float2( 0.92702072, 0.34599034),
+ float2(-0.17203432, 0.12048409),
+ float2(-0.40881620, 0.87902032),
+ float2( 0.11214125, -0.97011162),
+ float2( 0.35807629, 0.34593269),
+ float2(-0.93515467, -0.30090412),
+ float2( 0.96965589, -0.21669445),
+ float2(-0.12747712, -0.42799143),
+ float2(-0.04160416, 0.58750344),
+ float2(-0.50661284, -0.18463137),
+ float2(-0.49591186, 0.43573011),
+ float2( 0.69214410, 0.71546306),
+ float2( 0.58762817, -0.78906213),
+ float2( 0.60529434, -0.00157846),
+ float2( 0.18530521, -0.07537744),
+ float2(-0.06393139, 0.98782194),
+ float2(-0.24668936, -0.92075575),
+ float2( 0.81235073, -0.52916214),
+ float2( 0.18896697, -0.62996998),
+ float2(-0.71415530, 0.69260619),
+ float2(-0.65167829, 0.11466757),
+ float2(-0.65839165, -0.45386823),
+ float2( 0.40773627, 0.63990787),
+ float2(-0.99945967, -0.01288785),
+ float2( 0.06793334, 0.29985044),
+ float2( 0.88601041, 0.06665496),
+ float2( 0.63692110, 0.42919088),
+ float2(-0.38553272, -0.52927284),
+};
+
+static const float2 pcf_filter_disk[shadow_pcf_sample_count] = {
+ float2( 0.32558563, -0.24988839),
+ float2(-0.98541266, 0.16930865),
+ float2( 0.09145512, 0.89445213),
+ float2(-0.54480597, -0.82331975),
+ float2( 0.86243144, 0.42877010),
+ float2( 0.19152898, -0.98054135),
+ float2(-0.24839078, 0.19012049),
+ float2(-0.58789047, 0.78475191),
+ float2( 0.97505840, -0.19006157),
+ float2( 0.30273086, 0.33427269),
+ float2(-0.60614320, -0.24764520),
+ float2( 0.64000315, -0.68394018),
+ float2(-0.12301224, -0.53311522),
+ float2( 0.51234899, 0.75192892),
+ float2( 0.64313826, 0.06972717),
+ float2(-0.19284146, 0.60355651),
+ float2(-0.62280056, 0.36318874),
+ float2(-0.18834340, -0.95691492),
+ float2(-0.04911758, -0.13578936),
+ float2(-0.82927681, -0.54621998),
+ float2( 0.27020206, -0.61902601),
+ float2(-0.98076941, -0.18488425),
+ float2(-0.26883836, 0.96108127),
+ float2( 0.66283184, -0.32922370),
+ float2( 0.98983969, 0.13429859),
+ float2(-0.44329948, -0.53094113),
+ float2(-0.54192541, 0.06588807),
+ float2( 0.14739192, 0.59331660),
+ float2( 0.04982322, 0.14943985),
+ float2(-0.31222249, -0.26794820),
+ float2( 0.56008364, 0.46637058),
+ float2(-0.81663912, 0.57351727),
+ float2( 0.32731617, 0.05812120),
+ float2( 0.85294944, -0.52194453),
+ float2( 0.44306862, -0.87673132),
+ float2( 0.03380403, -0.76031090),
+ float2( 0.08711519, -0.36824602),
+ float2(-0.04387798, 0.39043461),
+ float2(-0.44689900, 0.54474622),
+ float2(-0.79730201, -0.01361312),
+ float2( 0.34065561, 0.93312502),
+ float2(-0.28571328, -0.73045171),
+ float2( 0.74645565, 0.64790973),
+ float2( 0.47432929, -0.49756161),
+ float2(-0.32838125, -0.02568294),
+ float2( 0.49288123, -0.09977098),
+ float2( 0.51299973, 0.24791173),
+ float2( 0.75389572, -0.12623179),
+ float2(-0.84467634, 0.34163260),
+ float2(-0.36987966, 0.76150517),
+ float2(-0.27850542, 0.40472485),
+ float2(-0.10969806, 0.80499616),
+ float2(-0.81179020, -0.32586517),
+ float2( 0.17068056, -0.09060725),
+ float2( 0.36889045, 0.58095936),
+ float2( 0.79213670, 0.22321366),
+ float2(-0.62388309, -0.63161735),
+ float2(-0.45122724, 0.24914915),
+ float2(-0.11527424, -0.33262249),
+ float2(-0.71985451, 0.17533603),
+ float2( 0.07976847, -0.56354086),
+ float2(-0.64407590, -0.43844161),
+ float2( 0.25012793, 0.75807218),
+ float2(-0.13113449, 0.03615541),
+};
+
+float find_blocker(float2 uv, float reference, float search_radius, out float blocker_depth) {
+ float blockers = 0.0;
+ blocker_depth = 0.0;
+ for (int index = 0; index < shadow_blocker_sample_count; index++) {
+ float depth = shadow_depth_map.SampleLevel(uv + blocker_search_disk[index] * search_radius, 0.0);
+ if (depth < reference) {
+ blocker_depth += depth;
+ blockers += 1.0;
+ }
+ }
+ if (blockers > 0.0) {
+ blocker_depth /= blockers;
+ }
+ return blockers;
+}
+
+float penumbra_size(float reference, float blocker_depth) {
+ return light.shadow_penumbra_scale * (reference - blocker_depth);
+}
+
+float pcf_filter(float2 uv, float reference, float filter_radius) {
+ float visibility = 0.0;
+ for (int index = 0; index < shadow_pcf_sample_count; index++) {
+ visibility += shadow_map.SampleCmpLevelZero(uv + pcf_filter_disk[index] * filter_radius, reference);
+ }
+ return visibility / float(shadow_pcf_sample_count);
+}
float shadow_visibility(float4 light_space_position, float normal_dot_light) {
float3 projected = light_space_position.xyz / light_space_position.w;
@@ -62,19 +197,17 @@ float shadow_visibility(float4 light_space_position, float normal_dot_light) {
return 1.0;
}
- float bias = max(light.shadow_maximum_bias * (1.0 - normal_dot_light), light.shadow_minimum_bias);
- float reference = projected.z - bias;
- float visibility = 0.0;
- float taps = 0.0;
- for (int y = -shadow_pcf_radius; y <= shadow_pcf_radius; y++) {
- for (int x = -shadow_pcf_radius; x <= shadow_pcf_radius; x++) {
- float2 offset = float2(x, y) * light.shadow_texel_size;
- visibility += shadow_map.SampleCmpLevelZero(shadow_sampler, uv + offset, reference);
- taps += 1.0;
- }
+ float bias = max(light.shadow_maximum_bias * (1.0 - normal_dot_light), light.shadow_minimum_bias);
+ float reference = projected.z - bias;
+
+ float search_radius = clamp(light.shadow_penumbra_scale * reference, light.shadow_texel_size, shadow_maximum_search_uv);
+ float blocker_depth;
+ if (find_blocker(uv, reference, search_radius, blocker_depth) == 0.0) {
+ return 1.0;
}
- return visibility / taps;
+ float filter_radius = clamp(penumbra_size(reference, blocker_depth), shadow_minimum_filter_texels * light.shadow_texel_size, shadow_maximum_filter_uv);
+ return pcf_filter(uv, reference, filter_radius);
}
FSOutput main(FSInput input) {
diff --git a/src/model.c b/src/model.c
index 2c78850..396e70a 100644
--- a/src/model.c
+++ b/src/model.c
@@ -145,7 +145,7 @@ typedef struct ta_model_light_uniforms {
float shadow_minimum_bias;
float shadow_maximum_bias;
float shadow_strength;
- float padding;
+ float shadow_penumbra_scale;
} ta_model_light_uniforms;
typedef struct ta_model_shadow_uniforms {
@@ -182,7 +182,7 @@ bool ta_model_init(ta_model *model, SDL_GPUDevice *device, const float positions
}
model->vertex_count = (Uint32)model->mesh.vertex_count;
SDL_GPUShader *vertex_shader = ta_model_shader(device, file_model_vert_slang_spv_start, file_model_vert_slang_spv_size, SDL_GPU_SHADERSTAGE_VERTEX, 0, 1);
- SDL_GPUShader *fragment_shader = ta_model_shader(device, file_model_frag_slang_spv_start, file_model_frag_slang_spv_size, SDL_GPU_SHADERSTAGE_FRAGMENT, 1, 1);
+ SDL_GPUShader *fragment_shader = ta_model_shader(device, file_model_frag_slang_spv_start, file_model_frag_slang_spv_size, SDL_GPU_SHADERSTAGE_FRAGMENT, 2, 1);
SDL_GPUVertexBufferDescription vertex_buffer = {.slot = 0, .pitch = sizeof(ta_model_vertex), .input_rate = SDL_GPU_VERTEXINPUTRATE_VERTEX};
SDL_GPUVertexAttribute attributes[2] = {
{
@@ -374,17 +374,24 @@ void ta_model_render(const ta_model *model, SDL_GPUCommandBuffer *command_buffer
ta_shadow_light_direction[1],
ta_shadow_light_direction[2]
},
- .shadow_texel_size = 1.0f / (float)TA_SHADOW_MAP_SIZE,
- .shadow_minimum_bias = ta_shadow_minimum_bias,
- .shadow_maximum_bias = ta_shadow_maximum_bias,
- .shadow_strength = ta_shadow_strength,
+ .shadow_texel_size = 1.0f / (float)TA_SHADOW_MAP_SIZE,
+ .shadow_minimum_bias = ta_shadow_minimum_bias,
+ .shadow_maximum_bias = ta_shadow_maximum_bias,
+ .shadow_strength = ta_shadow_strength,
+ .shadow_penumbra_scale = ta_shadow_penumbra_scale,
};
- SDL_GPUTextureSamplerBinding shadow_binding = {
- .texture = ta_shadow_texture,
- .sampler = ta_shadow_sampler
+ SDL_GPUTextureSamplerBinding shadow_bindings[2] = {
+ {
+ .texture = ta_shadow_texture,
+ .sampler = ta_shadow_sampler
+ },
+ {
+ .texture = ta_shadow_texture,
+ .sampler = ta_shadow_depth_sampler
+ },
};
SDL_PushGPUFragmentUniformData(command_buffer, 0, &light, sizeof(light));
- SDL_BindGPUFragmentSamplers(render_pass, 0, &shadow_binding, 1);
+ SDL_BindGPUFragmentSamplers(render_pass, 0, shadow_bindings, 2);
}
SDL_GPUBufferBinding binding = {
diff --git a/src/shadow.c b/src/shadow.c
index 2967674..469a3bf 100644
--- a/src/shadow.c
+++ b/src/shadow.c
@@ -28,6 +28,7 @@
SDL_GPUTexture *ta_shadow_texture;
SDL_GPUSampler *ta_shadow_sampler;
+SDL_GPUSampler *ta_shadow_depth_sampler;
float ta_shadow_light_direction[TA_SHADOW_DIMENSION] = { -0.45f, 0.75f, 0.55f };
@@ -35,6 +36,8 @@ float ta_shadow_normal_offset = 0.03f;
float ta_shadow_minimum_bias = 0.0005f;
float ta_shadow_maximum_bias = 0.003f;
float ta_shadow_strength = 1.0f;
+float ta_shadow_light_size = 0.04f;
+float ta_shadow_penumbra_scale;
static float ta_shadow_dot(const float *left, const float *right) {
return left[0] * right[0] + left[1] * right[1] + left[2] * right[2];
@@ -56,6 +59,8 @@ static void ta_shadow_normalize(float *vector) {
}
void ta_shadow_init(void) {
+ ta_shadow_penumbra_scale = ta_shadow_light_size * (TA_SHADOW_FAR - TA_SHADOW_NEAR) / (2.0f * TA_SHADOW_EXTENT);
+
SDL_GPUTextureCreateInfo texture_info = {
.type = SDL_GPU_TEXTURETYPE_2D,
.format = TA_SHADOW_FORMAT,
@@ -79,6 +84,16 @@ void ta_shadow_init(void) {
.enable_compare = true,
};
ta_shadow_sampler = ta_sdl_create_gpu_sampler(ta_gpu_device, &sampler_info);
+
+ SDL_GPUSamplerCreateInfo depth_sampler_info = {
+ .min_filter = SDL_GPU_FILTER_NEAREST,
+ .mag_filter = SDL_GPU_FILTER_NEAREST,
+ .mipmap_mode = SDL_GPU_SAMPLERMIPMAPMODE_NEAREST,
+ .address_mode_u = SDL_GPU_SAMPLERADDRESSMODE_CLAMP_TO_EDGE,
+ .address_mode_v = SDL_GPU_SAMPLERADDRESSMODE_CLAMP_TO_EDGE,
+ .address_mode_w = SDL_GPU_SAMPLERADDRESSMODE_CLAMP_TO_EDGE,
+ };
+ ta_shadow_depth_sampler = ta_sdl_create_gpu_sampler(ta_gpu_device, &depth_sampler_info);
}
void ta_shadow_get_light_view_projection(float *matrix) {
@@ -145,8 +160,10 @@ SDL_GPURenderPass *ta_shadow_begin_render_pass(SDL_GPUCommandBuffer *command_buf
}
void ta_shadow_shutdown(void) {
+ SDL_ReleaseGPUSampler(ta_gpu_device, ta_shadow_depth_sampler);
SDL_ReleaseGPUSampler(ta_gpu_device, ta_shadow_sampler);
SDL_ReleaseGPUTexture(ta_gpu_device, ta_shadow_texture);
+ ta_shadow_depth_sampler = NULL;
ta_shadow_sampler = NULL;
ta_shadow_texture = NULL;
} \ No newline at end of file
generated by cgit v1.2.3 (git 2.46.0) at 2026-09-26 07:26:35 +0000