From 95895750e836028a63ec5375dd06742a8d901df5 Mon Sep 17 00:00:00 2001
From: Abdelrahman <said.abdelrahman89@gmail.com>
Date: Fri, 13 Sep 2024 23:55:11 +0100
Subject: [PATCH] Split shaders code to separate files
---
src/shader/main_shader.c | 129 +++++++++++++++++++++++++++++++++++++
src/shader/main_shader.h | 19 ++++++
src/shader/shader_base.inc | 7 ++
3 files changed, 155 insertions(+)
create mode 100644 src/shader/main_shader.c
create mode 100644 src/shader/main_shader.h
create mode 100644 src/shader/shader_base.inc
diff --git a/src/shader/main_shader.c b/src/shader/main_shader.c
new file mode 100644
index 0000000..da95de8
--- /dev/null
+++ b/src/shader/main_shader.c
@@ -0,0 +1,129 @@
+#include "main_shader.h"
+#include "obj.h"
+#include "shader.h"
+#include "utils.h"
+#include "vec.h"
+
+VertexData general_shader_vertex(void *shader, const VertexData *vert, u8 index,
+ const Model *model) {
+ Shader *shdr = (Shader *)shader;
+
+ V4f vh = V3_to_V4(vert->position);
+ vh.y = 0.0 - vh.y;
+ vh = mat4x4_mul_vec4(shdr->final, vh);
+
+ shdr->vertices[index].position = project_vec4(vh);
+ shdr->vertices[index].uv = vert->uv;
+
+ M4x4f inv_transpose = mat4x4_inv(mat4x4_transpose(shdr->proj_mv));
+ V4f hnorm = V3_to_V4(vert->normal);
+ hnorm = mat4x4_mul_vec4(inv_transpose, hnorm);
+ shdr->vertices[index].normal = project_vec4(hnorm);
+ normalise_v3(shdr->vertices[index].normal);
+
+ return shdr->vertices[index];
+}
+
+FragmentResult diffuse_shader_fragment(void *shader, const V3f *barycentric,
+ const Colour *colour,
+ const Model *model) {
+ Shader *shdr = (Shader *)shader;
+
+ M3x3f pos_mat = {.rows = {shdr->vertices[0].position, shdr->vertices[1].position, shdr->vertices[2].position}};
+ pos_mat = mat3x3_transpose(pos_mat);
+ M3x3f normal_mat = {.rows = {shdr->vertices[0].normal, shdr->vertices[1].normal, shdr->vertices[2].normal}};
+ normal_mat = mat3x3_transpose(normal_mat);
+ M3x2f uvs = {shdr->vertices[0].uv, shdr->vertices[1].uv, shdr->vertices[2].uv};
+ M2x3f uv_mat = mat3x2_transpose(uvs);
+
+ V3f position = mat3x3_mul_vec3(pos_mat, (*barycentric));
+ V3f normal = mat3x3_mul_vec3(normal_mat, (*barycentric));
+ V2f uv = mat2x3_mul_vec3(uv_mat, (*barycentric));
+
+#pragma region darboux_frame_tangent_normals
+ /**
+ * Based on the following section of the tinyrenderer tutorial
+ * https://github.com/ssloy/tinyrenderer/wiki/Lesson-6bis:-tangent-space-normal-mapping#starting-point-phong-shading
+ */
+
+ if (model->normal) {
+ u64 nm_x = uv.u * model->normal->width;
+ u64 nm_y = uv.v * model->normal->height;
+
+ Colour pixel = get_pixel(Colour, model->normal, nm_x, nm_y);
+ V3f tangent = (V3f){
+ .x = pixel.r / 255.f * 2.f - 1.f,
+ .y = pixel.g / 255.f * 2.f - 1.f,
+ .z = pixel.b / 255.f * 2.f - 1.f,
+ };
+
+ V3f p0p1 = sub_v3(shdr->vertices[1].position, shdr->vertices[0].position);
+ V3f p0p2 = sub_v3(shdr->vertices[2].position, shdr->vertices[0].position);
+
+ M3x3f A = {.rows = {p0p1, p0p2, normal}};
+ M3x3f A_inv = mat3x3_inv(A);
+
+ V2f uv0 = shdr->vertices[0].uv;
+ V2f uv1 = shdr->vertices[1].uv;
+ V2f uv2 = shdr->vertices[2].uv;
+
+ V3f u_vec = {uv1.u - uv0.u, uv2.u - uv0.u, 0};
+ V3f v_vec = {uv1.v - uv0.v, uv2.v - uv0.v, 0};
+
+ V3f i = mat3x3_mul_vec3(A_inv, u_vec);
+ normalise_v3(i);
+ V3f j = mat3x3_mul_vec3(A_inv, v_vec);
+ normalise_v3(j);
+
+ M3x3f B = {.rows = {i, j, normal}};
+ B = mat3x3_transpose(B);
+
+ normal = mat3x3_mul_vec3(B, tangent);
+ normalise_v3(normal);
+ }
+#pragma endregion darboux_frame_tangent_normals
+
+ Colour output;
+ if (model->texture) {
+ u64 tx_x = uv.u * model->texture->width;
+ u64 tx_y = uv.v * model->texture->height;
+ output = get_pixel(Colour, model->texture, tx_x, tx_y);
+ } else {
+ output = *colour;
+ }
+
+ f32 intensity = max(0.001f, dot_v3(normal, shdr->light_dir));
+ f32 r = clamp(intensity + shdr->ambient.r, 0.0f, 1.0f);
+ f32 g = clamp(intensity + shdr->ambient.g, 0.0f, 1.0f);
+ f32 b = clamp(intensity + shdr->ambient.b, 0.0f, 1.0f);
+
+ output.r *= r;
+ output.g *= g;
+ output.b *= b;
+
+ return (FragmentResult){.colour = output};
+}
+
+FragmentResult albedo_shader_fragment(void *shader, const V3f *barycentric,
+ const Colour *colour,
+ const Model *model) {
+ Shader *shdr = (Shader *)shader;
+
+ // clang-format off
+ M3x2f uvs = {shdr->vertices[0].uv, shdr->vertices[1].uv, shdr->vertices[2].uv};
+ M2x3f uv_mat = mat3x2_transpose(uvs);
+ // clang-format on
+
+ V2f uv = mat2x3_mul_vec3(uv_mat, (*barycentric));
+
+ Colour output;
+ if (model->texture) {
+ u64 tx_x = uv.u * model->texture->width;
+ u64 tx_y = uv.v * model->texture->height;
+ output = get_pixel(Colour, model->texture, tx_x, tx_y);
+ } else {
+ output = *colour;
+ }
+
+ return (FragmentResult){.colour = output};
+}
diff --git a/src/shader/main_shader.h b/src/shader/main_shader.h
new file mode 100644
index 0000000..5f5fdfe
--- /dev/null
+++ b/src/shader/main_shader.h
@@ -0,0 +1,19 @@
+#ifndef MAIN_SHADER_H
+#define MAIN_SHADER_H
+
+#include "shader.h"
+#include "vec.h"
+
+typedef struct shader Shader;
+struct shader {
+#include "shader_base.inc"
+};
+
+VertexData general_shader_vertex(void *shader, const VertexData *vert, u8 index,
+ const Model *model);
+FragmentResult diffuse_shader_fragment(void *shader, const V3f *barycentric,
+ const Colour *colour,
+ const Model *model);
+FragmentResult albedo_shader_fragment(void *shader, const V3f *barycentric,
+ const Colour *colour, const Model *model);
+#endif // !MAIN_SHADER_H
diff --git a/src/shader/shader_base.inc b/src/shader/shader_base.inc
new file mode 100644
index 0000000..5fb7dc7
--- /dev/null
+++ b/src/shader/shader_base.inc
@@ -0,0 +1,7 @@
+V3f light_dir;
+V3f ambient;
+M4x4f proj_mv;
+M4x4f proj_mv_inv_t;
+M4x4f viewport;
+M4x4f final;
+VertexData vertices[TRIANGLE_VERTICES];