Create shaders

src/main.c

@@ -1,9 +1,10 @@
-#include "aliases.h"
 #include "img.h"
 #include "mem_arena.h"
 #include "mem_utils.h"
 #include "obj.h"
-#include "vec.h"
+#include "shader.h"
+#include "shaders.h"
+#include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -12,10 +13,12 @@
 #define SIZE 1200
 #define RESOURCE(NAME) "resources/" NAME
 
-V3f g_eye = {0.2f, 0.1f, 0.75f};
-V3f g_target = {0};
-V3f g_up = {0.0f, 1.0f, 0.0f};
-M4x4f g_cam_matrix = mat4x4_identity;
+extern ShaderID perspective_lit_textured_id;
+extern ShaderID perspective_lit_coloured_id;
+extern ShaderID perspective_albedo_id;
+extern ShaderID orthographic_lit_textured_id;
+extern ShaderID orthographic_lit_coloured_id;
+extern ShaderID orthographic_albedo_id;
 
 enum {
   TINY_EXIT_SUCCESS,
@@ -24,10 +27,6 @@ enum {
   TINY_EXIT_MODEL_LOAD_FAILED,
 };
 
-internal M4x4f get_projection_matrix(ProjectionType projection_type);
-internal V3f main_shader_vertex(const V3f *vertex, M4x4f *model_view,
-                                M4x4f *projection, const Image *img);
-
 int main(void) {
   Arena *arena = NULL;
   if (!wapp_mem_arena_init(&arena, 10ul * 1024ul * 1024ul * 1024ul,
@@ -49,44 +48,14 @@ int main(void) {
     return TINY_EXIT_MODEL_LOAD_FAILED;
   }
 
-  M4x4f model_view = lookat(g_eye, g_target, g_up);
-  M4x4f perspective_projection =
-      get_projection_matrix(PROJECTION_TYPE_PERSPECTIVE);
-
-  Shader main_shader = {
-      .vertex = main_shader_vertex,
-      .model_view = &model_view,
-      .projection = &perspective_projection,
-  };
+  load_shaders();
 
   clear_buffer(&(render.img), &bg);
-  render_model(&obj, &render, &main_shader, RENDER_TYPE_SHADED, teal);
+  render_model(&obj, &render, perspective_lit_textured_id, RENDER_TYPE_SHADED,
+               teal);
   save_image(&(render.img), "result.pam");
 
   wapp_mem_arena_destroy(&arena);
 
   return TINY_EXIT_SUCCESS;
 }
-
-internal M4x4f get_projection_matrix(ProjectionType projection_type) {
-  if (projection_type == PROJECTION_TYPE_PERSPECTIVE) {
-    // Calculate projection matrix
-    V3f cam = V3(V3f, f32, g_target.x, g_target.y, g_target.z, g_eye.x, g_eye.y,
-                 g_eye.z);
-    normalise_v3(cam);
-    f32 coeff = -1.0f / magnitude_v3(cam) * 0.5f;
-    return projection(coeff);
-  }
-
-  return mat4x4_identity;
-}
-
-internal V3f main_shader_vertex(const V3f *vertex, M4x4f *model_view,
-                                M4x4f *projection, const Image *img) {
-  V4f vh = {.x = vertex->x, .y = vertex->y, .z = vertex->z, .w = 1.0f};
-  vh = mat4x4_mul_vec4((*projection), mat4x4_mul_vec4((*model_view), vh));
-  vh.y = 0.0 - vh.y;
-  vh = mat4x4_mul_vec4(viewport(vh.x, vh.y, img->width, img->height), vh);
-
-  return project_vec4(vh);
-}

src/shaders.c

@@ -0,0 +1,148 @@
+#include "img.h"
+#include "obj.h"
+#include "shader.h"
+#include "utils.h"
+#include "vec.h"
+
+typedef struct shader Shader;
+struct shader {
+  M4x4f model_view;
+  M4x4f projection;
+};
+
+Shader perspective = {0};
+Shader orthographic = {0};
+
+ShaderID perspective_lit_textured_id = {0};
+ShaderID perspective_lit_coloured_id = {0};
+ShaderID perspective_albedo_id = {0};
+ShaderID orthographic_lit_textured_id = {0};
+ShaderID orthographic_lit_coloured_id = {0};
+ShaderID orthographic_albedo_id = {0};
+
+V3f g_light_dir = {0.0f, 0.0f, 1.0f};
+V3f g_eye = {0.2f, 0.1f, 0.75f};
+V3f g_target = {0};
+V3f g_up = {0.0f, 1.0f, 0.0f};
+M4x4f g_cam_matrix = mat4x4_identity;
+
+internal V3f general_shader_vertex(void *shader, const V3f *vertex,
+                                   const Buffer *out_buf);
+internal FragmentResult lit_textured_shader_fragment(void *shader, V3f normal,
+                                                     V2f tex_coords,
+                                                     const Colour *colour,
+                                                     const Image *texture);
+internal FragmentResult lit_coloured_shader_fragment(void *shader, V3f normal,
+                                                     V2f tex_coords,
+                                                     const Colour *colour,
+                                                     const Image *texture);
+internal FragmentResult albedo_shader_fragment(void *shader, V3f normal,
+                                               V2f tex_coords,
+                                               const Colour *colour,
+                                               const Image *texture);
+internal M4x4f get_projection_matrix(ProjectionType projection_type);
+internal f32 get_intensity(const V3f *normal);
+
+void load_shaders(void) {
+  M4x4f model_view = lookat(g_eye, g_target, g_up);
+  M4x4f orthographic_projection =
+      get_projection_matrix(PROJECTION_TYPE_ORTHOGRAPHIC);
+  M4x4f perspective_projection =
+      get_projection_matrix(PROJECTION_TYPE_PERSPECTIVE);
+
+  perspective.model_view = orthographic.model_view = model_view;
+  perspective.projection = perspective_projection;
+  orthographic.projection = orthographic_projection;
+
+  perspective_lit_textured_id = create_shader(
+      &perspective, general_shader_vertex, lit_textured_shader_fragment);
+  perspective_lit_coloured_id = create_shader(
+      &perspective, general_shader_vertex, lit_coloured_shader_fragment);
+  perspective_albedo_id = create_shader(&perspective, general_shader_vertex,
+                                        albedo_shader_fragment);
+  orthographic_lit_textured_id = create_shader(
+      &orthographic, general_shader_vertex, lit_textured_shader_fragment);
+  orthographic_lit_coloured_id = create_shader(
+      &orthographic, general_shader_vertex, lit_coloured_shader_fragment);
+  orthographic_albedo_id = create_shader(&orthographic, general_shader_vertex,
+                                         albedo_shader_fragment);
+}
+
+internal V3f general_shader_vertex(void *shader, const V3f *vertex,
+                                   const Buffer *out_buf) {
+  Shader *shader_ptr = (Shader *)shader;
+
+  V4f vh = {.x = vertex->x, .y = vertex->y, .z = vertex->z, .w = 1.0f};
+  vh = mat4x4_mul_vec4(shader_ptr->projection,
+                       mat4x4_mul_vec4(shader_ptr->model_view, vh));
+  vh.y = 0.0 - vh.y;
+  vh = mat4x4_mul_vec4(viewport(vh.x, vh.y, out_buf->width, out_buf->height),
+                       vh);
+
+  return project_vec4(vh);
+}
+
+internal FragmentResult lit_textured_shader_fragment(void *shader, V3f normal,
+                                                     V2f tex_coords,
+                                                     const Colour *colour,
+                                                     const Image *texture) {
+  if (!texture) {
+    return DISCARDED_FRAGMENT;
+  }
+
+  f32 intensity = get_intensity(&normal);
+
+  u64 tx_x = tex_coords.u * texture->width;
+  u64 tx_y = (1.0f - tex_coords.v) * texture->height;
+
+  Colour output = get_pixel(Colour, texture, tx_x, tx_y);
+
+  output.r *= intensity;
+  output.g *= intensity;
+  output.b *= intensity;
+
+  return (FragmentResult){.colour = output};
+}
+
+internal FragmentResult lit_coloured_shader_fragment(void *shader, V3f normal,
+                                                     V2f tex_coords,
+                                                     const Colour *colour,
+                                                     const Image *texture) {
+  f32 intensity = get_intensity(&normal);
+  Colour output = *colour;
+
+  output.r *= intensity;
+  output.g *= intensity;
+  output.b *= intensity;
+
+  return (FragmentResult){.colour = output};
+}
+
+internal FragmentResult albedo_shader_fragment(void *shader, V3f normal,
+                                               V2f tex_coords,
+                                               const Colour *colour,
+                                               const Image *texture) {
+  return (FragmentResult){.colour = *colour};
+}
+
+internal M4x4f get_projection_matrix(ProjectionType projection_type) {
+  if (projection_type == PROJECTION_TYPE_PERSPECTIVE) {
+    // Calculate projection matrix
+    V3f cam = V3(V3f, f32, g_target.x, g_target.y, g_target.z, g_eye.x, g_eye.y,
+                 g_eye.z);
+    normalise_v3(cam);
+    f32 coeff = -1.0f / magnitude_v3(cam) * 0.5f;
+    return projection(coeff);
+  }
+
+  return mat4x4_identity;
+}
+
+internal f32 get_intensity(const V3f *normal) {
+  f32 intensity = dot_v3((*normal), g_light_dir);
+  if (intensity < 0.0f) {
+    intensity = 0.01f;
+  }
+
+  return intensity;
+}

src/shaders.h

@@ -0,0 +1,6 @@
+#ifndef SHADERS_H
+#define SHADERS_H
+
+void load_shaders(void);
+
+#endif // SHADERS_H