creating shadowmap pipeline

6 files changed, 134 insertions, 11 deletions

diff --git a/assets/shaders/shadows.frag b/assets/shaders/shadows.frag
new file mode 100644
index 0000000..0876b66
--- /dev/null
+++ b/assets/shaders/shadows.frag
@@ -0,0 +1,5 @@
+#version 410 core
+
+void main() {
+  gl_FragDepth = gl_FragCoord.z;
+}
\ No newline at end of file
diff --git a/assets/shaders/shadows.vert b/assets/shaders/shadows.vert
new file mode 100644
index 0000000..00b1a81
--- /dev/null
+++ b/assets/shaders/shadows.vert
@@ -0,0 +1,19 @@
+#version 410 core
+
+// Vertex attributes
+layout(location = 0) in vec3 inPosition;
+layout(location = 1) in vec3 inNormal;
+layout(location = 2) in vec2 inTexCoords;
+
+// Uniforms
+uniform Model {
+  mat4 mat;
+};
+
+uniform LightSpace {
+  mat4 mat;
+};
+
+void main() {
+  gl_Position = LightSpace.mat * Model.mat * vec4(inPosition, 1.0);
+}
diff --git a/examples/shadow_maps/ex_shadow_maps.c b/examples/shadow_maps/ex_shadow_maps.c
index e4f7f8a..1423d7a 100644
--- a/examples/shadow_maps/ex_shadow_maps.c
+++ b/examples/shadow_maps/ex_shadow_maps.c
@@ -17,6 +17,11 @@ const vec3 pointlight_positions[4] = {
 };
 point_light point_lights[4];
 
+/*
+  TODO:
+- keyboard button to switch between main camera and light camera
+*/
+
 int main() {
   core_bringup();
   arena scratch = arena_create(malloc(1024 * 1024), 1024 * 1024);
@@ -28,8 +33,13 @@ int main() {
   ren_shadowmaps shadows = { .width = 1000, .height = 1000 };
   // ren_shadowmaps_init(&shadows);
 
-  // Meshes
-  mesh cubes[4];
+  // Set up the scene
+  // We want:
+  // 1. a ground plane
+  // 2. lights
+  // 3. some boxes
+
+  mesh scene[5];
   for (int i = 0; i < 4; i++) {
     geometry_data geo = geo_create_cuboid(f32x3(2,2,2));
     cubes[i] = mesh_create(&geo, true);
diff --git a/src/renderer/backends/opengl/backend_opengl.c b/src/renderer/backends/opengl/backend_opengl.c
index 8f52674..ea10acb 100644
--- a/src/renderer/backends/opengl/backend_opengl.c
+++ b/src/renderer/backends/opengl/backend_opengl.c
@@ -152,6 +152,11 @@ gpu_renderpass* gpu_renderpass_create(const gpu_renderpass_desc* description) {
     glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_TEXTURE_2D, depth_attachment->id, 0); 
   }
 
+  if (description->has_depth_stencil && !description->has_color_target) {
+    glDrawBuffer(GL_NONE);
+    glReadBuffer(GL_NONE);
+  }
+
   glBindFramebuffer(GL_FRAMEBUFFER, 0); // reset to default framebuffer
 
   return renderpass;
@@ -336,6 +341,10 @@ texture_handle gpu_texture_create(texture_desc desc, bool create_view, const voi
 
   glBindTexture(GL_TEXTURE_2D, gl_texture_id);
 
+  GLint internal_format = desc.format == CEL_TEXTURE_FORMAT_DEPTH_DEFAULT ?  GL_DEPTH_COMPONENT : GL_RGB;
+  GLenum format = desc.format == CEL_TEXTURE_FORMAT_DEPTH_DEFAULT ? GL_DEPTH_COMPONENT : GL_RGBA;
+  GLenum data_type = desc.format == CEL_TEXTURE_FORMAT_DEPTH_DEFAULT ? GL_FLOAT : GL_UNSIGNED_BYTE;
+
   // set the texture wrapping parameters
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S,
                   GL_REPEAT);  // set texture wrapping to GL_REPEAT (default wrapping method)
@@ -345,12 +354,15 @@ texture_handle gpu_texture_create(texture_desc desc, bool create_view, const voi
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
 
   if (data) {
-    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, desc.extents.x, desc.extents.y, 0,
-                 GL_RGBA,  // TODO: convert format to GL enum
-                 GL_UNSIGNED_BYTE, data);
+    glTexImage2D(GL_TEXTURE_2D, 0, internal_format, desc.extents.x, desc.extents.y, 0,
+                 format,
+                 data_type, data);
     glGenerateMipmap(GL_TEXTURE_2D);
   } else {
     WARN("No image data provided");
+    glTexImage2D(GL_TEXTURE_2D, 0, internal_format, desc.extents.x, desc.extents.y, 0,
+                 format,
+                 data_type, NULL);
   }
 
   glBindTexture(GL_TEXTURE_2D, 0);
diff --git a/src/renderer/renderpasses.c b/src/renderer/renderpasses.c
index d28df3d..3f2152f 100644
--- a/src/renderer/renderpasses.c
+++ b/src/renderer/renderpasses.c
@@ -13,10 +13,15 @@
 #include "maths_types.h"
 #include "ral.h"
 #include "ral_types.h"
+#include "file.h"
 
 #define SHADOW_WIDTH 1000
 #define SHADOW_HEIGHT 1000
 
+void ren_shadowmaps_init(ren_shadowmaps* storage) {
+  storage->rpass = shadowmaps_renderpass_create();
+  storage->static_pipeline = shadowmaps_pipeline_create(storage->rpass);
+}
 
 gpu_renderpass* shadowmaps_renderpass_create() {
   // Create depthmap texture
@@ -37,11 +42,83 @@ gpu_renderpass* shadowmaps_renderpass_create() {
   return gpu_renderpass_create(&shadows_desc);
 }
 
-gpu_pipeline* shadowmaps_pipeline_create() {
-  // struct graphics_pipeline_desc desc = {
-  //   .
-  // };
-  // gpu_graphics_pipeline_create(struct graphics_pipeline_desc description)
+// == shader bindings
+typedef struct model_uniform {
+  mat4 model;
+} model_uniform;
+
+typedef struct lightspace_tf_uniform {
+  mat4 lightSpaceMatrix;
+} lightspace_tf_uniform;
+
+shader_data_layout model_uniform_layout(void* data) {
+  bool has_data = data != NULL;
+
+  shader_binding b1 = {
+    .label = "Model",
+    .type = SHADER_BINDING_BYTES,
+    .stores_data = has_data,
+    .data = {.bytes.size = sizeof(model_uniform)}
+  };
+  if (has_data) {
+    b1.data.bytes.data = data;
+  }
+  return (shader_data_layout){ .name = "model_uniform", .bindings = {b1}, .bindings_count = 1};
+}
+shader_data_layout lightspace_uniform_layout(void* data) {
+  bool has_data = data != NULL;
+
+  shader_binding b1 = {
+    .label = "LightSpace",
+    .type = SHADER_BINDING_BYTES,
+    .stores_data = has_data,
+    .data = {.bytes.size = sizeof(lightspace_tf_uniform)}
+  };
+  if (has_data) {
+    b1.data.bytes.data = data;
+  }
+  return (shader_data_layout){ .name = "lightspace_tf_uniform", .bindings = {b1}, .bindings_count = 1};
+}
+
+// ==================
+
+gpu_pipeline* shadowmaps_pipeline_create(gpu_renderpass* rpass) {
+  arena scratch = arena_create(malloc(1024 * 1024), 1024 * 1024);
+
+  str8 vert_path = str8lit("assets/shaders/shadows.vert");
+  str8 frag_path = str8lit("assets/shaders/shadows.frag");
+  str8_opt vertex_shader = str8_from_file(&scratch, vert_path);
+  str8_opt fragment_shader = str8_from_file(&scratch, frag_path);
+  if (!vertex_shader.has_value || !fragment_shader.has_value) {
+    ERROR_EXIT("Failed to load shaders from disk");
+  }
+
+  // We'll have two data layouts. 1. for the light-space transform, and 2. for the model matrix
+  shader_data model_uniform = {.data = NULL, .shader_data_get_layout = &model_uniform_layout };
+    shader_data lightspace_uniform = {.data = NULL, .shader_data_get_layout = &lightspace_uniform_layout };
+
+  struct graphics_pipeline_desc desc = {
+    .debug_name = "Shadowmap drawing pipeline",
+    .vertex_desc = static_3d_vertex_description(),
+    .data_layouts = { model_uniform, lightspace_uniform },
+    .data_layouts_count = 2,
+    .vs = {
+      .debug_name = "Shadows Vert shader",
+      .filepath = vert_path,
+      .code = vertex_shader.contents,
+      .is_spirv = true
+    },
+    .fs = {
+      .debug_name = "Shadows Frag shader",
+      .filepath = vert_path,
+      .code = vertex_shader.contents,
+      .is_spirv = true
+    },
+    .renderpass = rpass
+  };
+
+  arena_free_storage(&scratch);
+  return gpu_graphics_pipeline_create(desc);
 }
 
 void renderpass_shadowmap_execute(gpu_renderpass* pass, render_entity* entities, size_t entity_count) {
diff --git a/src/renderer/renderpasses.h b/src/renderer/renderpasses.h
index 4a689e6..3ee3b6e 100644
--- a/src/renderer/renderpasses.h
+++ b/src/renderer/renderpasses.h
@@ -32,6 +32,6 @@ typedef struct ren_shadowmaps {
 void ren_shadowmaps_init(ren_shadowmaps* storage);
 
 gpu_renderpass* shadowmaps_renderpass_create();
-gpu_pipeline* shadowmaps_pipeline_create();
+gpu_pipeline* shadowmaps_pipeline_create(gpu_renderpass* rpass);
 
 void renderpass_shadowmap_execute(gpu_renderpass* pass, render_entity* entities, size_t entity_count);