new sample shadows-depthtex-sapp (wip)

sapp/CMakeLists.txt

@@ -139,6 +139,20 @@ fips_begin_app(shadows-sapp-ui windowed)
     target_compile_definitions(shadows-sapp-ui PRIVATE USE_DBG_UI)
 fips_end_app()
 
+fips_ide_group(Samples)
+fips_begin_app(shadows-depthtex-sapp windowed)
+    fips_files(shadows-depthtex-sapp.c)
+    sokol_shader(shadows-depthtex-sapp.glsl ${slang})
+    fips_deps(sokol)
+fips_end_app()
+fips_ide_group(SamplesWithDebugUI)
+fips_begin_app(shadows-depthtex-sapp-ui windowed)
+    fips_files(shadows-depthtex-sapp.c)
+    sokol_shader(shadows-depthtex-sapp.glsl ${slang})
+    fips_deps(sokol dbgui)
+    target_compile_definitions(shadows-depthtex-sapp-ui PRIVATE USE_DBG_UI)
+fips_end_app()
+
 fips_ide_group(Samples)
 fips_begin_app(instancing-sapp windowed)
     fips_files(instancing-sapp.c)

sapp/shadows-depthtex-sapp.c

@@ -0,0 +1,269 @@
+//------------------------------------------------------------------------------
+//  shadows-depthtex-sapp.c
+//
+//  Shadow mapping via a depth-buffer texture.
+//
+//  - depth-only shadow pass (no color render targets)
+//  - display pass samples shadow map with a comparison sampler
+//------------------------------------------------------------------------------
+#include "sokol_app.h"
+#include "sokol_gfx.h"
+#include "sokol_log.h"
+#include "sokol_glue.h"
+#include "dbgui/dbgui.h"
+#define HANDMADE_MATH_IMPLEMENTATION
+#define HANDMADE_MATH_NO_SSE
+#include "HandmadeMath.h"
+#include "shadows-depthtex-sapp.glsl.h"
+
+static struct {
+    sg_image shadow_map;
+    sg_sampler shadow_sampler;
+    sg_buffer vbuf;
+    sg_buffer ibuf;
+    float ry;
+    struct {
+        sg_pass_action pass_action;
+        sg_pass pass;
+        sg_pipeline pip;
+        sg_bindings bind;
+    } shadow;
+    struct {
+        sg_pass_action pass_action;
+        sg_pipeline pip;
+        sg_bindings bind;
+    } display;
+} state;
+
+static void init(void) {
+    sg_setup(&(sg_desc){
+        .context = sapp_sgcontext(),
+        .logger.func = slog_func,
+    });
+    __dbgui_setup(sapp_sample_count());
+
+    // FIXME: replace with sokol-shape:
+    // cube vertex buffer with positions & normals
+    const float vertices[] = {
+        // pos                  normals
+        -1.0f, -1.0f, -1.0f,    0.0f, 0.0f, -1.0f,  //CUBE BACK FACE
+         1.0f, -1.0f, -1.0f,    0.0f, 0.0f, -1.0f,
+         1.0f,  1.0f, -1.0f,    0.0f, 0.0f, -1.0f,
+        -1.0f,  1.0f, -1.0f,    0.0f, 0.0f, -1.0f,
+
+        -1.0f, -1.0f,  1.0f,    0.0f, 0.0f, 1.0f,   //CUBE FRONT FACE
+         1.0f, -1.0f,  1.0f,    0.0f, 0.0f, 1.0f,
+         1.0f,  1.0f,  1.0f,    0.0f, 0.0f, 1.0f,
+        -1.0f,  1.0f,  1.0f,    0.0f, 0.0f, 1.0f,
+
+        -1.0f, -1.0f, -1.0f,    -1.0f, 0.0f, 0.0f,  //CUBE LEFT FACE
+        -1.0f,  1.0f, -1.0f,    -1.0f, 0.0f, 0.0f,
+        -1.0f,  1.0f,  1.0f,    -1.0f, 0.0f, 0.0f,
+        -1.0f, -1.0f,  1.0f,    -1.0f, 0.0f, 0.0f,
+
+         1.0f, -1.0f, -1.0f,    1.0f, 0.0f, 0.0f,   //CUBE RIGHT FACE
+         1.0f,  1.0f, -1.0f,    1.0f, 0.0f, 0.0f,
+         1.0f,  1.0f,  1.0f,    1.0f, 0.0f, 0.0f,
+         1.0f, -1.0f,  1.0f,    1.0f, 0.0f, 0.0f,
+
+        -1.0f, -1.0f, -1.0f,    0.0f, -1.0f, 0.0f,  //CUBE BOTTOM FACE
+        -1.0f, -1.0f,  1.0f,    0.0f, -1.0f, 0.0f,
+         1.0f, -1.0f,  1.0f,    0.0f, -1.0f, 0.0f,
+         1.0f, -1.0f, -1.0f,    0.0f, -1.0f, 0.0f,
+
+        -1.0f,  1.0f, -1.0f,    0.0f, 1.0f, 0.0f,   //CUBE TOP FACE
+        -1.0f,  1.0f,  1.0f,    0.0f, 1.0f, 0.0f,
+         1.0f,  1.0f,  1.0f,    0.0f, 1.0f, 0.0f,
+         1.0f,  1.0f, -1.0f,    0.0f, 1.0f, 0.0f,
+
+        -1.0f,  0.0f, -1.0f,    0.0f, 1.0f, 0.0f,   //PLANE GEOMETRY
+        -1.0f,  0.0f,  1.0f,    0.0f, 1.0f, 0.0f,
+         1.0f,  0.0f,  1.0f,    0.0f, 1.0f, 0.0f,
+         1.0f,  0.0f, -1.0f,    0.0f, 1.0f, 0.0f,
+    };
+    state.vbuf = sg_make_buffer(&(sg_buffer_desc){
+        .data = SG_RANGE(vertices),
+        .label = "cube-vertices"
+    });
+
+    // an index buffer for the cube
+    const uint16_t indices[] = {
+        0, 1, 2,  0, 2, 3,
+        6, 5, 4,  7, 6, 4,
+        8, 9, 10,  8, 10, 11,
+        14, 13, 12,  15, 14, 12,
+        16, 17, 18,  16, 18, 19,
+        22, 21, 20,  23, 22, 20,
+        26, 25, 24,  27, 26, 24
+    };
+    state.ibuf = sg_make_buffer(&(sg_buffer_desc){
+        .type = SG_BUFFERTYPE_INDEXBUFFER,
+        .data = SG_RANGE(indices),
+        .label = "cube-indices"
+    });
+
+    // shadow map pass action: only clear depth buffer, don't configure color and stencil actions,
+    // because there are no color and stencil targets
+    state.shadow.pass_action = (sg_pass_action){
+        .depth = {
+            .load_action = SG_LOADACTION_CLEAR,
+            .store_action = SG_STOREACTION_STORE,
+            .clear_value = 1.0f,
+        },
+    };
+
+    // a shadow map render target which will serve as depth buffer
+    state.shadow_map = sg_make_image(&(sg_image_desc){
+        .render_target = true,
+        .width = 1024,
+        .height = 1024,
+        .pixel_format = SG_PIXELFORMAT_DEPTH,
+        .sample_count = 1,
+        .label = "shadow-map",
+    });
+
+    // a comparison sampler which is used to sample the shadow map texture in the display pass
+    state.shadow_sampler = sg_make_sampler(&(sg_sampler_desc){
+        .min_filter = SG_FILTER_NEAREST,
+        .mag_filter = SG_FILTER_NEAREST,
+        .wrap_u = SG_WRAP_CLAMP_TO_EDGE,
+        .wrap_v = SG_WRAP_CLAMP_TO_EDGE,
+        .compare = SG_COMPAREFUNC_GREATER,
+        .label = "shadow-sampler",
+    });
+
+    // a pass object for the shadow pass
+    state.shadow.pass = sg_make_pass(&(sg_pass_desc){
+        .depth_stencil_attachment.image = state.shadow_map,
+        .label = "shadow-pass",
+    });
+
+    // a pipeline object for the shadow pass
+    state.shadow.pip = sg_make_pipeline(&(sg_pipeline_desc){
+        .layout = {
+            // need to provide vertex stride, because normal component is skipped in shadow pass
+            .buffers[0].stride = 6 * sizeof(float),
+            .attrs = {
+                [ATTR_vs_shadow_pos].format = SG_VERTEXFORMAT_FLOAT3,
+            },
+        },
+        .shader = sg_make_shader(shadow_shader_desc(sg_query_backend())),
+        .index_type = SG_INDEXTYPE_UINT16,
+        // FIXME!
+        .cull_mode = SG_CULLMODE_NONE,
+        .sample_count = 1,
+        // important: 'deactivate' the default color target
+        .colors[0].pixel_format = SG_PIXELFORMAT_NONE,
+        .depth = {
+            .pixel_format = SG_PIXELFORMAT_DEPTH,
+            .compare = SG_COMPAREFUNC_LESS_EQUAL,
+            .write_enabled = true,
+        },
+        // NOTE: no color targets
+        .label = "shadow-pipeline"
+    });
+
+    // a pipeline object for the display pass
+    state.display.pip = sg_make_pipeline(&(sg_pipeline_desc){
+        .layout = {
+            .attrs = {
+                [ATTR_vs_display_pos].format = SG_VERTEXFORMAT_FLOAT3,
+                [ATTR_vs_display_norm].format = SG_VERTEXFORMAT_FLOAT3,
+            }
+        },
+        .shader = sg_make_shader(display_shader_desc(sg_query_backend())),
+        .index_type = SG_INDEXTYPE_UINT16,
+        // FIXME
+        .cull_mode = SG_CULLMODE_NONE,
+        .depth = {
+            .compare = SG_COMPAREFUNC_LESS_EQUAL,
+            .write_enabled = true,
+        },
+        .label = "display-pipeline",
+    });
+
+    // resource bindings to render shadow scene
+    state.shadow.bind = (sg_bindings) {
+        .vertex_buffers[0] = state.vbuf,
+        .index_buffer = state.ibuf,
+    };
+
+    // resource bindings to render display scene
+    state.shadow.bind = (sg_bindings) {
+        .vertex_buffers[0] = state.vbuf,
+        .index_buffer = state.ibuf,
+        .fs = {
+            .images[SLOT_shadow_map] = state.shadow_map,
+            .samplers[SLOT_shadow_sampler] = state.shadow_sampler,
+        },
+    };
+}
+
+static void frame(void) {
+    const float t = (float)(sapp_frame_duration() * 60.0);
+    state.ry += 0.2f * t;
+
+    // calculate transform matrices for plane and cube
+    const hmm_mat4 scale = HMM_Scale(HMM_Vec3(5.0f, 0.0f, 5.0f));
+    const hmm_mat4 translate = HMM_Translate(HMM_Vec3(0.0f, 1.5f, 0.0f));
+
+    // calculate matrices for shadow pass
+    const hmm_mat4 rym = HMM_Rotate(state.ry, HMM_Vec3(0.0f, 1.0f, 0.0f));
+    const hmm_vec4 light_dir = HMM_MultiplyMat4ByVec4(rym, HMM_Vec4(50.0f, 50.0f, -50.0f, 0.0f));
+    const hmm_mat4 light_view = HMM_LookAt(light_dir.XYZ, HMM_Vec3(0.0f, 0.0f, 0.0f), HMM_Vec3(0.0f, 1.0f, 0.0f));
+
+    // configure a bias matrix for converting view-space coordinates into uv coordinates
+    hmm_mat4 light_proj = { {
+        { 0.5f, 0.0f, 0.0f, 0 },
+        { 0.0f, 0.5f, 0.0f, 0 },
+        { 0.0f, 0.0f, 0.5f, 0 },
+        { 0.5f, 0.5f, 0.5f, 1 }
+    } };
+    light_proj = HMM_MultiplyMat4(light_proj, HMM_Orthographic(-4.0f, 4.0f, -4.0f, 4.0f, 0, 200.0f));
+    const hmm_mat4 light_view_proj = HMM_MultiplyMat4(light_proj, light_view);
+
+    const vs_shadow_params_t vs_shadow_params = {
+        .mvp = HMM_MultiplyMat4(light_view_proj, translate)
+    };
+
+    // calculate matrices for display pass
+    const hmm_mat4 proj = HMM_Perspective(60.0f, sapp_widthf()/sapp_heightf(), 0.01f, 100.0f);
+    const hmm_mat4 view = HMM_LookAt(HMM_Vec3(5.0f, 5.0f, 5.0f), HMM_Vec3(0.0f, 0.0f, 0.0f), HMM_Vec3(0.0f, 1.0f, 0.0f));
+    const hmm_mat4 view_proj = HMM_MultiplyMat4(proj, view);
+
+
+    // the shadow map pass, render scene into shadow map texture
+    sg_begin_pass(state.shadow.pass, &state.shadow.pass_action);
+    sg_apply_pipeline(state.shadow.pip);
+    sg_apply_bindings(&state.shadow.bind);
+    sg_apply_uniforms(SG_SHADERSTAGE_VS, SLOT_vs_shadow_params, &SG_RANGE(vs_shadow_params));
+    sg_draw(0, 36, 1);
+    sg_end_pass();
+
+    // FIXME
+    sg_begin_default_pass(&state.display.pass_action, sapp_width(), sapp_height());
+    __dbgui_draw();
+    sg_end_pass();
+    sg_commit();
+}
+
+static void cleanup(void) {
+    __dbgui_shutdown();
+    sg_shutdown();
+}
+
+sapp_desc sokol_main(int argc, char* argv[]) {
+    (void)argc; (void)argv;
+    return (sapp_desc){
+        .init_cb = init,
+        .frame_cb = frame,
+        .cleanup_cb = cleanup,
+        .event_cb = __dbgui_event,
+        .width = 800,
+        .height = 600,
+        .sample_count = 4,
+        .window_title = "shadows-depthtex-sapp",
+        .icon.sokol_default = true,
+        .logger.func = slog_func,
+    };
+}

sapp/shadows-depthtex-sapp.glsl

@@ -0,0 +1,53 @@
+@ctype mat4 hmm_mat4
+@ctype vec3 hmm_vec3
+
+// shadow pass
+@vs vs_shadow
+
+uniform vs_shadow_params {
+    mat4 mvp;
+};
+
+in vec4 pos;
+void main() {
+    gl_Position = mvp * pos;
+}
+@end
+
+@fs fs_shadow
+void main() {
+    discard;
+}
+@end
+
+@program shadow vs_shadow fs_shadow
+
+// display pass
+@vs vs_display
+
+uniform vs_display_params {
+    mat4 mvp;
+};
+
+in vec4 pos;
+in vec3 norm;
+
+void main() {
+    gl_Position = mvp * pos;
+}
+@end
+
+@fs fs_display
+
+uniform texture2D shadow_map;
+uniform sampler shadow_sampler;
+
+out vec4 frag_color;
+
+void main() {
+    float s = texture(sampler2DShadow(shadow_map, shadow_sampler), vec3(0, 0, 1));
+    frag_color = vec4(s, s, s, 1.0);
+}
+@end
+
+@program display vs_display fs_display