matrix
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jb
parent
38ea89c4a6
commit
6be5527b37
@ -7,6 +7,7 @@ set(CMAKE_C_STANDARD 11)
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add_executable(${PROJECT_NAME} scripts/main.c
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scripts/array.c
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scripts/vector.c
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scripts/matrix.c
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scripts/mesh.c
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scripts/triangle.c
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scripts/display.c)
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@ -8,6 +8,7 @@
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#include "mesh.h"
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#include "vector.h"
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#include "array.h"
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#include "matrix.h"
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#define STEP 0.075
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@ -113,8 +114,8 @@ void process_input(void) {
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////////////////////////////////////////////////////////////////////////////////
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vec2_t project(vec3_t point) {
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vec2_t projected_point = {
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.x = round((fov_factor * point.x) / point.z),
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.y = round((fov_factor * point.y) / point.z),
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.x = roundf((fov_factor * point.x) / point.z),
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.y = roundf((fov_factor * point.y) / point.z),
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};
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return projected_point;
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}
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@ -131,9 +132,27 @@ void update(void) {
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previous_frame_time = SDL_GetTicks();
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mesh.rotation.y += 0.01;
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mesh.rotation.x -= 0.01;
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mesh.rotation.z += 0.01;
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mesh.rotation.y += 0.01f;
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mesh.rotation.x -= 0.01f;
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mesh.rotation.z += 0.01f;
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mesh.translation.x += 0.004f;
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mesh.translation.z = 5.0f;
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//mesh.scale.x += 0.002f;
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//mesh.scale.y += 0.002f;
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// create scale matrix that will be used
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mat4_t scale_matrix = mat4_make_scale(mesh.scale.x, mesh.scale.y, mesh.scale.z);
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// create translation matrix
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mat4_t translation_matrix = mat4_make_translation(mesh.translation.x, mesh.translation.y, mesh.translation.z);
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// create rotation matrices
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mat4_t rotation_matrix_x = mat4_make_rotation_x(mesh.rotation.x);
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mat4_t rotation_matrix_y = mat4_make_rotation_y(mesh.rotation.y);
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mat4_t rotation_matrix_z = mat4_make_rotation_z(mesh.rotation.z);
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triangles_to_render = NULL;
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@ -146,17 +165,21 @@ void update(void) {
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face_vertices[1] = mesh.vertices[mesh_face.b - 1];
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face_vertices[2] = mesh.vertices[mesh_face.c - 1];
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vec3_t transformed_vertices[3];
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vec4_t transformed_vertices[3];
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for (int j = 0; j < 3; j++) {
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vec3_t transformed_vertex = face_vertices[j];
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vec4_t transformed_vertex = vec4_from_vec3(face_vertices[j]);
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transformed_vertex = vec3_rotate_x(transformed_vertex, mesh.rotation.x);
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transformed_vertex = vec3_rotate_y(transformed_vertex, mesh.rotation.y);
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transformed_vertex = vec3_rotate_z(transformed_vertex, mesh.rotation.z);
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// use matrix to scale original matrix
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transformed_vertex = mat4_multiply_vec4(scale_matrix, transformed_vertex);
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// translate away from camera in z
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transformed_vertex.z += 5;
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// use matrices to rotate
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transformed_vertex = mat4_multiply_vec4(rotation_matrix_x, transformed_vertex);
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transformed_vertex = mat4_multiply_vec4(rotation_matrix_y, transformed_vertex);
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transformed_vertex = mat4_multiply_vec4(rotation_matrix_z, transformed_vertex);
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// use matrix to translate
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transformed_vertex = mat4_multiply_vec4(translation_matrix, transformed_vertex);
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// save translated vertex in the array of transformed vertices
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transformed_vertices[j] = transformed_vertex;
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@ -164,9 +187,9 @@ void update(void) {
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if (cull_method == CULL_BACKFACE) {
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// check backface culling
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vec3_t vector_a = transformed_vertices[0]; /* A */
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vec3_t vector_b = transformed_vertices[1]; /* / \ */
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vec3_t vector_c = transformed_vertices[2]; /* C---B */
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vec3_t vector_a = vec3_from_vec4(transformed_vertices[0]); /* A */
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vec3_t vector_b = vec3_from_vec4(transformed_vertices[1]); /* / \ */
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vec3_t vector_c = vec3_from_vec4(transformed_vertices[2]); /* C---B */
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// get the vector subtraction of B-A and C-A
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vec3_t vector_ab = vec3_subtract(vector_b, vector_a);
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@ -193,7 +216,7 @@ void update(void) {
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for (int j = 0; j < 3; j++) {
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// project the current vertex
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vec2_t projected_point = project(transformed_vertices[j]);
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vec2_t projected_point = project(vec3_from_vec4(transformed_vertices[j]));
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// scale and translate the projected points to the center of the screen
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projected_point.x += (window_width / 2);
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@ -221,8 +244,8 @@ int depth_comp(const void* a, const void* b) {
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triangle_t arg_a = *(const triangle_t*)a;
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triangle_t arg_b = *(const triangle_t*)b;
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if (arg_a.average_depth < arg_b.average_depth) return -1;
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if (arg_a.average_depth > arg_b.average_depth) return 1;
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if (arg_a.average_depth > arg_b.average_depth) return -1;
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if (arg_a.average_depth < arg_b.average_depth) return 1;
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return 0;
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}
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103
scripts/matrix.c
Normal file
103
scripts/matrix.c
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@ -0,0 +1,103 @@
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#include "matrix.h"
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mat4_t mat4_identity(void) {
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mat4_t m = {{
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{ 1, 0, 0, 0},
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{ 0, 1, 0, 0},
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{ 0, 0, 1, 0},
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{ 0, 0, 0, 1},
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}};
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return m;
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}
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mat4_t mat4_make_scale(float sx, float sy, float sz) {
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mat4_t m = mat4_identity();
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m.m[0][0] *= sx;
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m.m[1][1] *= sy;
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m.m[2][2] *= sz;
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return m;
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}
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mat4_t mat4_make_translation(float tx, float ty, float tz) {
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/*
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* 1 0 0 tx
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* 0 1 0 ty
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* 0 0 1 tz
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* 0 0 0 1
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*/
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mat4_t m = mat4_identity();
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m.m[0][3] = tx;
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m.m[1][3] = ty;
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m.m[2][3] = tz;
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return m;
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}
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mat4_t mat4_make_rotation_y(float ra) {
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/*
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* cos 0 -sin 0
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* 0 1 0 0
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* sin 0 cos 0
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* 0 0 0 1
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*/
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const float cosine = cosf(ra);
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const float sine = sinf(ra);
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mat4_t m = mat4_identity();
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m.m[0][0] = cosine;
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m.m[0][2] = -sine;
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m.m[2][0] = sine;
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m.m[2][2] = cosine;
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return m;
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}
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mat4_t mat4_make_rotation_x(float ra) {
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/*
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* 1 0 0 0
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* 0 cos sin 0
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* 0 -sin cos 0
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* 0 0 0 1
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*/
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const float cosine = cosf(ra);
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const float sine = sinf(ra);
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mat4_t m = mat4_identity();
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m.m[1][1] = cosine;
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m.m[1][2] = sine;
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m.m[2][1] = -sine;
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m.m[2][2] = cosine;
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return m;
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}
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mat4_t mat4_make_rotation_z(float ra) {
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/*
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* cos sin 0 0
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* -sin cos 0 0
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* 0 0 1 0
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* 0 0 0 1
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*/
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const float cosine = cosf(ra);
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const float sine = sinf(ra);
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mat4_t m = mat4_identity();
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m.m[0][0] = cosine;
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m.m[0][1] = sine;
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m.m[1][0] = -sine;
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m.m[1][1] = cosine;
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return m;
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}
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vec4_t mat4_multiply_vec4(mat4_t m, vec4_t v) {
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vec4_t ret = {};
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ret.x = m.m[0][0] * v.x + m.m[0][1] * v.y + m.m[0][2] * v.z + m.m[0][3] * v.w;
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ret.y = m.m[1][0] * v.x + m.m[1][1] * v.y + m.m[1][2] * v.z + m.m[1][3] * v.w;
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ret.z = m.m[2][0] * v.x + m.m[2][1] * v.y + m.m[2][2] * v.z + m.m[2][3] * v.w;
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ret.w = m.m[3][0] * v.x + m.m[3][1] * v.y + m.m[3][2] * v.z + m.m[3][3] * v.w;
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return ret;
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}
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21
scripts/matrix.h
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21
scripts/matrix.h
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@ -0,0 +1,21 @@
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#ifndef MATRIX_H
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#define MATRIX_H
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#include <math.h>
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#include "vector.h"
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typedef struct mat4_t mat4_t;
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struct mat4_t {
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float m[4][4];
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};
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mat4_t mat4_identity(void);
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mat4_t mat4_make_scale(float sx, float sy, float sz);
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mat4_t mat4_make_translation(float tx, float ty, float tz);
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mat4_t mat4_make_rotation_x(float ra);
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mat4_t mat4_make_rotation_y(float ra);
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mat4_t mat4_make_rotation_z(float ra);
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vec4_t mat4_multiply_vec4(mat4_t m, vec4_t v);
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#endif
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@ -11,7 +11,9 @@
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mesh_t mesh = {
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.vertices = NULL,
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.faces = NULL,
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.rotation = { 0, 0, 0 }
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.rotation = { 0, 0, 0 },
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.scale = { 1.0, 1.0, 1.0 },
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.translation = { 0, 0, 0 },
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};
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vec3_t cube_vertices[N_CUBE_VERTICES] = {
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@ -32,6 +32,8 @@ struct mesh_t {
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vec3_t* vertices;
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face_t* faces;
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vec3_t rotation;
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vec3_t scale;
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vec3_t translation;
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};
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extern mesh_t mesh;
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@ -122,4 +122,22 @@ void vec3_normalize(vec3_t* vertex) {
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vertex->x /= length;
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vertex->y /= length;
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vertex->z /= length;
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}
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vec4_t vec4_from_vec3(vec3_t vertex) {
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vec4_t ret;
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ret.x = vertex.x;
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ret.y = vertex.y;
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ret.z = vertex.z;
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ret.w = 1;
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return ret;
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}
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vec3_t vec3_from_vec4(vec4_t v) {
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return (vec3_t) {
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.x = v.x,
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.y = v.y,
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.z = v.z,
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};
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}
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@ -12,6 +12,10 @@ typedef struct {
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float z;
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} vec3_t;
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typedef struct {
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float x, y, z, w;
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} vec4_t;
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// TODO: Add functions to manipulate vectors 2D and 3D
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// ...
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@ -36,4 +40,7 @@ float vec3_length(const vec3_t vector);
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float vec3_dot(const vec3_t a, const vec3_t b);
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void vec3_normalize(vec3_t* vertex);
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vec4_t vec4_from_vec3(vec3_t vertex);
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vec3_t vec3_from_vec4(vec4_t v);
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#endif
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