127 lines
4.2 KiB
C
127 lines
4.2 KiB
C
#include "main_shader.h"
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#include "obj.h"
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#include "shader.h"
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#include "utils.h"
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#include "vec.h"
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VertexData general_shader_vertex(void *shader, const VertexData *vert, u8 index, const Model *model) {
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Shader *shdr = (Shader *)shader;
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V4f vh = V3_to_V4(vert->position);
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vh.y = 0.0 - vh.y;
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vh = mat4x4_mul_vec4(shdr->final, vh);
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shdr->vertices[index].position = project_vec4(vh);
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shdr->vertices[index].uv = vert->uv;
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M4x4f inv_transpose = mat4x4_inv(mat4x4_transpose(shdr->proj_mv));
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V4f hnorm = V3_to_V4(vert->normal);
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hnorm = mat4x4_mul_vec4(inv_transpose, hnorm);
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shdr->vertices[index].normal = project_vec4(hnorm);
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normalise_v3(shdr->vertices[index].normal);
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return shdr->vertices[index];
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}
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FragmentResult diffuse_shader_fragment(void *shader, const V3f *barycentric, const Colour *colour,
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const Model *model) {
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Shader *shdr = (Shader *)shader;
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M3x3f pos_mat = {.rows = {shdr->vertices[0].position, shdr->vertices[1].position, shdr->vertices[2].position}};
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pos_mat = mat3x3_transpose(pos_mat);
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M3x3f normal_mat = {.rows = {shdr->vertices[0].normal, shdr->vertices[1].normal, shdr->vertices[2].normal}};
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normal_mat = mat3x3_transpose(normal_mat);
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M3x2f uvs = {shdr->vertices[0].uv, shdr->vertices[1].uv, shdr->vertices[2].uv};
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M2x3f uv_mat = mat3x2_transpose(uvs);
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V3f position = mat3x3_mul_vec3(pos_mat, (*barycentric));
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V3f normal = mat3x3_mul_vec3(normal_mat, (*barycentric));
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V2f uv = mat2x3_mul_vec3(uv_mat, (*barycentric));
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#pragma region darboux_frame_tangent_normals
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/**
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* Based on the following section of the tinyrenderer tutorial
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* https://github.com/ssloy/tinyrenderer/wiki/Lesson-6bis:-tangent-space-normal-mapping#starting-point-phong-shading
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*/
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if (model->normal) {
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u64 nm_x = uv.u * model->normal->width;
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u64 nm_y = uv.v * model->normal->height;
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Colour pixel = get_pixel(Colour, model->normal, nm_x, nm_y);
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V3f tangent = (V3f){
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.x = pixel.r / 255.f * 2.f - 1.f,
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.y = pixel.g / 255.f * 2.f - 1.f,
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.z = pixel.b / 255.f * 2.f - 1.f,
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};
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V3f p0p1 = sub_v3(shdr->vertices[1].position, shdr->vertices[0].position);
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V3f p0p2 = sub_v3(shdr->vertices[2].position, shdr->vertices[0].position);
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M3x3f A = {.rows = {p0p1, p0p2, normal}};
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M3x3f A_inv = mat3x3_inv(A);
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V2f uv0 = shdr->vertices[0].uv;
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V2f uv1 = shdr->vertices[1].uv;
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V2f uv2 = shdr->vertices[2].uv;
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V3f u_vec = {uv1.u - uv0.u, uv2.u - uv0.u, 0};
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V3f v_vec = {uv1.v - uv0.v, uv2.v - uv0.v, 0};
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V3f i = mat3x3_mul_vec3(A_inv, u_vec);
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normalise_v3(i);
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V3f j = mat3x3_mul_vec3(A_inv, v_vec);
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normalise_v3(j);
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M3x3f B = {.rows = {i, j, normal}};
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B = mat3x3_transpose(B);
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normal = mat3x3_mul_vec3(B, tangent);
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normalise_v3(normal);
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}
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#pragma endregion darboux_frame_tangent_normals
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Colour output;
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if (model->texture) {
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u64 tx_x = uv.u * model->texture->width;
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u64 tx_y = uv.v * model->texture->height;
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output = get_pixel(Colour, model->texture, tx_x, tx_y);
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} else {
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output = *colour;
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}
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f32 intensity = max(0.001f, dot_v3(normal, shdr->light_dir));
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f32 r = clamp(intensity + shdr->ambient.r, 0.0f, 1.0f);
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f32 g = clamp(intensity + shdr->ambient.g, 0.0f, 1.0f);
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f32 b = clamp(intensity + shdr->ambient.b, 0.0f, 1.0f);
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output.r *= r;
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output.g *= g;
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output.b *= b;
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return (FragmentResult){.colour = output};
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}
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FragmentResult albedo_shader_fragment(void *shader, const V3f *barycentric, const Colour *colour,
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const Model *model) {
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Shader *shdr = (Shader *)shader;
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// clang-format off
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M3x2f uvs = {shdr->vertices[0].uv, shdr->vertices[1].uv, shdr->vertices[2].uv};
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M2x3f uv_mat = mat3x2_transpose(uvs);
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// clang-format on
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V2f uv = mat2x3_mul_vec3(uv_mat, (*barycentric));
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Colour output;
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if (model->texture) {
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u64 tx_x = uv.u * model->texture->width;
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u64 tx_y = uv.v * model->texture->height;
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output = get_pixel(Colour, model->texture, tx_x, tx_y);
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} else {
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output = *colour;
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}
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return (FragmentResult){.colour = output};
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}
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