basic vector operations

build.sh

@@ -2,4 +2,4 @@
 
 set -xe
 
-gcc -g -Wall -Wextra -o main main.c
+gcc -g -Wall -Wextra -o main main.c -lm

gmath.h

@@ -1,9 +1,11 @@
 #ifndef GMATH_H
 #define GMATH_H
+#define PI 3.1415926535
 
 #define GMAT_AT(m, r, c)	((m).mat[(r) * (m).width + (c)])
 
 #include <stdio.h>
+#include <math.h>
 
 typedef struct {
 	float *mat;
@@ -11,6 +13,8 @@ typedef struct {
 	short height;
 } Matrix;
 
+typedef enum { GMatrix_Rotation_X, GMatrix_Rotation_Y, GMatrix_Rotation_Z} GMatrix_Rotation;
+
 Matrix GMatrix_malloc(short width, short height);
 void GMatrix_fill(Matrix mat, float var);
 
@@ -26,6 +30,10 @@ void GMatrix_sub(Matrix dest, const Matrix mat);
 void GMatrix_scal(Matrix dest, int val);
 void GMatrix_prod(Matrix dest, const Matrix mat1, const Matrix mat2);
 
+void GMatrix_vector_scale(Matrix dest, float x, float y, float z);
+void GMatrix_vector_translate(Matrix dest, float x, float y, float z);
+void GMatrix_vector_rotate(Matrix dest, float d, GMatrix_Rotation r);
+
 #endif
 
 #ifdef GMATH_IMPLEMENTATION
@@ -35,6 +43,11 @@ void GMatrix_prod(Matrix dest, const Matrix mat1, const Matrix mat2);
 #define GMATH_MALLOC malloc
 #endif
 
+#ifndef GMATH_MEMCPY
+#include <string.h>
+#define GMATH_MEMCPY memcpy
+#endif
+
 #ifndef GMATH_ASSERT
 #include <assert.h>
 #define GMATH_ASSERT(n) assert((n))
@@ -107,10 +120,61 @@ void GMatrix_prod(Matrix dest, const Matrix mat1, const Matrix mat2){
 		for(int column = 0; column < dest.width; column++){
 			GMAT_AT(dest, row, column) = 0;
 			for(int i=0; i < mat1.width; i++){
-				GMAT_AT(dest, row, column) += GMAT_AT(mat1, row, i) * GMAT_AT(mat2, column, i);
+				GMAT_AT(dest, row, column) += GMAT_AT(mat1, row, i) * GMAT_AT(mat2, i,column);
 			}
 		}
 	}
 }
 
+void GMatrix_vector_scale(Matrix dest, float x, float y, float z){
+	Matrix trans = GMatrix_unit(4);
+	GMAT_AT(trans, 0, 0) = x;
+	GMAT_AT(trans, 1, 1) = y;
+	GMAT_AT(trans, 2, 2) = z;
+	Matrix ret = {.mat=GMATH_MALLOC(sizeof(float)*dest.width*dest.height), .width=dest.width, .height=dest.height};
+	GMATH_MEMCPY(ret.mat, dest.mat, sizeof(float)*dest.width*dest.height);
+	GMatrix_prod(dest, ret, trans);
+	free(ret.mat);
+}
+
+void GMatrix_vector_translate(Matrix dest, float x, float y, float z){
+	Matrix trans = GMatrix_unit(4);
+	GMAT_AT(trans, 0, 3) = x;
+	GMAT_AT(trans, 1, 3) = y;
+	GMAT_AT(trans, 2, 3) = z;
+	Matrix ret = {.mat=GMATH_MALLOC(sizeof(float)*dest.width*dest.height), .width=dest.width, .height=dest.height};
+	GMATH_MEMCPY(ret.mat, dest.mat, sizeof(float)*dest.width*dest.height);
+	GMatrix_prod(dest, ret, trans);
+	free(ret.mat);
+}
+
+
+void GMatrix_vector_rotate(Matrix dest, float d, GMatrix_Rotation r){
+	Matrix trans = GMatrix_unit(4);
+	switch (r) {
+		case GMatrix_Rotation_X:
+			GMAT_AT(trans, 1, 1) = cosf(d);
+			GMAT_AT(trans, 1, 2) = -sinf(d);
+			GMAT_AT(trans, 2, 1) = sinf(d);
+			GMAT_AT(trans, 2, 2) = cosf(d);
+			break;
+		case GMatrix_Rotation_Y:
+			GMAT_AT(trans, 0, 0) = cosf(d);
+			GMAT_AT(trans, 0, 2) = sinf(d);
+			GMAT_AT(trans, 2, 0) = -sinf(d);
+			GMAT_AT(trans, 2, 2) = cosf(d);
+			break;
+		case GMatrix_Rotation_Z:
+			GMAT_AT(trans, 0, 0) = cosf(d);
+			GMAT_AT(trans, 0, 1) = -sinf(d);
+			GMAT_AT(trans, 1, 0) = sinf(d);
+			GMAT_AT(trans, 1, 1) = cosf(d);
+			break;
+	}
+	Matrix ret = {.mat=GMATH_MALLOC(sizeof(float)*dest.width*dest.height), .width=dest.width, .height=dest.height};
+	GMATH_MEMCPY(ret.mat, dest.mat, sizeof(float)*dest.width*dest.height);
+	GMatrix_prod(dest, ret, trans);
+	free(ret.mat);
+}
+
 #endif

main.c

@@ -2,49 +2,26 @@
 #include "gmath.h"
 #include <stdio.h>
 
+
 int main(void)
 {
-	float matrix_shape[] = {
+	Matrix trans = GMatrix_unit(4); 
-		1, 2, 3,
+	GMatrix_print(trans);
-		4, 5, 6,
-		7, 8, 9,
-	};
-
-	float matrix_shape2[] = {
-		9, 8, 7,
-		6, 5, 4,
-		3, 2, 1,
-	};
-
-	float matrix_shape3[] = {
-		3,
-		4,
-		5,
-		1,
-	};
-
-	/* Matrix mat[3] = { */
-	/* 	{matrix_shape, 3, 3}, */
-	/* 	{matrix_shape2, 3, 3}, */
-	/* 	GMatrix_malloc(3,3), */
-	/* }; */
-
-	Matrix mat[3] = {
-		GMatrix_unit(4),
-		{matrix_shape3, 1, 4},
-		GMatrix_malloc(1, 4),
-	};
-
-	GMAT_AT(mat[0], 0, 3) = 1;
-	GMAT_AT(mat[0], 1, 3) = 1;
-	GMAT_AT(mat[0], 2, 3) = 1;
-
-
-	GMatrix_print(mat[0]);
 	printf("----------------------------------------\n");
-	GMatrix_print(mat[1]);
 
-	GMatrix_prod(mat[2], mat[0], mat[1]);
+	GMatrix_vector_translate(trans, 2, 3 ,4); 
+	GMatrix_print(trans);
+	printf("----------------------------------------\n");
+
+	GMatrix_vector_scale(trans, 2, 1 ,0.5); 
+	GMatrix_print(trans);
+	printf("----------------------------------------\n");
+
+	GMatrix_vector_rotate(trans, PI* 0.5, GMatrix_Rotation_X); 
+	GMatrix_print(trans);
+	printf("----------------------------------------\n");
+
+	GMatrix_vector_rotate(trans, PI, GMatrix_Rotation_Y); 
+	GMatrix_print(trans);
 	printf("----------------------------------------\n");
-	GMatrix_print(mat[2]);
 }