diff options
Diffstat (limited to 'src/linear.c')
| -rw-r--r-- | src/linear.c | 243 |
1 files changed, 243 insertions, 0 deletions
diff --git a/src/linear.c b/src/linear.c index e69de29..06c2e33 100644 --- a/src/linear.c +++ b/src/linear.c @@ -0,0 +1,243 @@ +#include "linear.h" +#include <math.h> + +mat4 +linearLookAt(vec3 position, vec3 target, vec3 world_up) +{ + mat4 out = linearMat4Identity(); + mat4 translate; + vec3 cam_dir, cam_right, cam_up; + /* position - target */ + cam_dir = linearVec3Add(position, linearVec3ScalarMulp(target, -1.0)); + cam_dir = linearVec3Normalize(cam_dir); + + cam_right = linearVec3CrossProduct(world_up, cam_dir); + cam_right = linearVec3Normalize(cam_right); + + cam_up = linearVec3CrossProduct(cam_dir, cam_right); + + int i; + for (i = 0; i < 3; i++) { + out.matrix[0][i] = cam_right.vector[i]; + out.matrix[1][i] = cam_up.vector[i]; + out.matrix[2][i] = cam_dir.vector[i]; + } + translate = linearTranslate(-position.vector[0], + -position.vector[1], + -position.vector[2]); + return linearMat4Mul(out, translate); +} + +mat4 +linearPerspective(float FoV, float ratio, float near, float far) +{ + mat4 out = linearMat4Fill(0.0); + float FoV_radians = FoV * M_PI / 180; + float width = near * tanf(FoV_radians) * ratio; + float height = near * tanf(FoV_radians); + + out.matrix[0][0] = near / width; + out.matrix[1][1] = near / height; + out.matrix[2][2] = -(far + near) / (far - near); + out.matrix[2][3] = -2 * far * near / (far - near); + out.matrix[3][2] = -1; + return out; +} + +mat4 +linearTranslate(float T_x, float T_y, float T_z) +{ + mat4 out = linearMat4Identity(); + out.matrix[0][3] = T_x; + out.matrix[1][3] = T_y; + out.matrix[2][3] = T_z; + return out; +} + +mat4 +linearTranslatev(vec3 T) +{ + return linearTranslate(T.vector[0], T.vector[1], T.vector[2]); +} + +mat4 +linearScale(float S_x, float S_y, float S_z) +{ + mat4 out = linearMat4Identity(); + out.matrix[0][0] = S_x; + out.matrix[1][1] = S_y; + out.matrix[2][2] = S_z; + return out; +} + +mat4 +linearScalev(vec3 S) +{ + return linearScale(S.vector[0], S.vector[1], S.vector[2]); +} + +mat4 +linearRotate(float degree, vec3 R_xyz) +{ + mat4 out = linearMat4Identity(); + vec3 R_xyz_normalized = linearVec3Normalize(R_xyz); + float radians = degree * M_PI/180.0; + float Rx = R_xyz_normalized.vector[0]; + float Ry = R_xyz_normalized.vector[1]; + float Rz = R_xyz_normalized.vector[2]; + float rcos = cosf(radians); + float rsin = sinf(radians); + + out.matrix[0][0] = rcos + pow(Rx, 2) * ( 1 - rcos); + out.matrix[0][1] = Rx * Ry * (1 - rcos) - Rz * rsin; + out.matrix[0][2] = Rx * Rz * (1 - rcos) + Ry * rsin; + + out.matrix[1][0] = Rx * Ry * (1 - rcos) + Rz * rsin; + out.matrix[1][1] = rcos + pow(Ry, 2) * ( 1 - rcos); + out.matrix[1][2] = Ry * Rz * (1 - rcos) - Rx * rsin; + + out.matrix[2][0] = Rz * Rx * (1 - rcos) - Ry * rsin; + out.matrix[2][1] = Ry * Rz * (1 - rcos) + Rx * rsin; + out.matrix[2][2] = rcos + pow(Rz, 2) * ( 1 - rcos); + return out; +} + +mat4 +linearMat4Fill(float value) +{ + int i, j; + mat4 out; + for (i = 0; i < 4; i++) { + for (j = 0; j < 4; j++) { + out.matrix[i][j] = value; + } + } + return out; +} + +mat4 +linearMat4Identity() +{ + int i, j; + mat4 out; + for (i = 0; i < 4; i++) { + for (j = 0; j < 4; j++) { + if (i == j) out.matrix[i][j] = 1.0; + else out.matrix[i][j] = 0.0; + } + } + return out; +} + +mat4 +linearMat4Transpose(mat4 x) +{ + mat4 out; + int i, j; + for (i = 0; i < 4; i++) { + for (j = 0; j < 4; j++) { + out.matrix[i][j] = x.matrix[j][i]; + } + } + return out; +} + +mat4 +linearMat4Mul(mat4 x1, mat4 x2) +{ + mat4 out; + int i, j, k; + for (i = 0; i < 4; i++) { + for (j = 0; j < 4; j++) { + out.matrix[i][j] = 0.0; + for (k = 0; k < 4; k++) + out.matrix[i][j] += x1.matrix[i][k] * x2.matrix[k][j]; + } + } + return out; +} + +mat4 +linearMat4Add(mat4 x1, mat4 x2) +{ + int i, j; + mat4 out; + for (i = 0; i < 4; i++) { + for (j = 0; j < 4; j++) { + out.matrix[i][j] = x1.matrix[i][j] + x2.matrix[i][j]; + } + } + return out; +} + +float +linearMat4Det(mat4 x) +{ + return 0.0; +} + +vec3 +linearVec3ScalarMulp(vec3 x, float scalar) +{ + vec3 out; + int i; + for (i = 0; i < 3; i++) { + out.vector[i] = scalar * x.vector[i]; + } + return out; +} + +vec3 +linearVec3(float x, float y, float z) +{ + vec3 out; + out.vector[0] = x; + out.vector[1] = y; + out.vector[2] = z; + return out; +} + +vec3 +linearVec3Add(vec3 x, vec3 y) +{ + vec3 out; + int i; + for (i = 0; i < 3; i++) { + out.vector[i] = x.vector[i] + y.vector[i]; + } + return out; +} + +vec3 +linearVec3Normalize(vec3 x) +{ + vec3 out; + float norm = sqrtf(linearVec3DotProduct(x, x)); + int i; + if (norm == 0) return x; + for (i = 0; i < 3; i++) { + out.vector[i] = x.vector[i] / norm; + } + return out; +} + +vec3 +linearVec3CrossProduct(vec3 x, vec3 y) +{ + vec3 out; + out.vector[0] = x.vector[1] * y.vector[2] - x.vector[2] * y.vector[1]; + out.vector[1] = - x.vector[0] * y.vector[2] + x.vector[2] * y.vector[0]; + out.vector[2] = x.vector[0] * y.vector[1] - x.vector[1] * y.vector[0]; + return out; +} + +float +linearVec3DotProduct(vec3 x, vec3 y) +{ + float out = 0; + int i; + for (i = 0; i < 3; i++) { + out += x.vector[i] * y.vector[i]; + } + return out; +} |