scummvm/graphics/tinygl/matrix.cpp

#define FORBIDDEN_SYMBOL_EXCEPTION_fprintf
#define FORBIDDEN_SYMBOL_EXCEPTION_stderr

#include "graphics/tinygl/zgl.h"

namespace TinyGL {

void gl_print_matrix(const float *m) {
	for (int i = 0; i < 4; i++) {
		fprintf(stderr, "%f %f %f %f\n", m[i], m[4 + i], m[8 + i], m[12 + i]);
	}
}

static inline void gl_matrix_update(GLContext *c) {
	c->matrix_model_projection_updated = (c->matrix_mode <= 1);
}

void glopMatrixMode(GLContext *c, GLParam *p) {
	int mode = p[1].i;
	switch (mode) {
	case TGL_MODELVIEW:
		c->matrix_mode = 0;
		break;
	case TGL_PROJECTION:
		c->matrix_mode = 1;
		break;
	case TGL_TEXTURE:
		c->matrix_mode = 2;
		break;
	default:
		assert(0);
	}
}

void glopLoadMatrix(GLContext *c, GLParam *p) {
	Matrix4 *m;
	GLParam *q;

	m = c->matrix_stack_ptr[c->matrix_mode];
	q = p + 1;

	for (int i = 0; i < 4; i++) {
		m->set(0,i, q[0].f); 
		m->set(1,i, q[1].f); 
		m->set(2,i, q[2].f); 
		m->set(3,i, q[3].f); 
		q += 4;
	}

	gl_matrix_update(c);
}

void glopLoadIdentity(GLContext *c, GLParam *) {
	*c->matrix_stack_ptr[c->matrix_mode] = Matrix4::identity();

	gl_matrix_update(c);
}

void glopMultMatrix(GLContext *c, GLParam *p) {
	Matrix4 m;
	GLParam *q;
	q = p + 1;

	for (int i = 0; i < 4; i++) {
		m.set(0,i,q[0].f);
		m.set(1,i,q[1].f);
		m.set(2,i,q[2].f);
		m.set(3,i,q[3].f);
		q += 4;
	}

	*c->matrix_stack_ptr[c->matrix_mode] = (*c->matrix_stack_ptr[c->matrix_mode]) * m;

	gl_matrix_update(c);
}


void glopPushMatrix(GLContext *c, GLParam *) {
	int n = c->matrix_mode;
	Matrix4 *m;

	assert((c->matrix_stack_ptr[n] - c->matrix_stack[n] + 1) < c->matrix_stack_depth_max[n]);

	m = ++c->matrix_stack_ptr[n];

	m[0] = m[-1];

	gl_matrix_update(c);
}

void glopPopMatrix(GLContext *c, GLParam *) {
	int n = c->matrix_mode;

	assert(c->matrix_stack_ptr[n] > c->matrix_stack[n]);
	c->matrix_stack_ptr[n]--;
	gl_matrix_update(c);
}

void glopRotate(GLContext *c, GLParam *p) {
	Matrix4 m;
	float u[3];
	float angle;
	int dir_code;

	angle = (float)(p[1].f * LOCAL_PI / 180.0);
	u[0] = p[2].f;
	u[1] = p[3].f;
	u[2] = p[4].f;

	// simple case detection
	dir_code = ((u[0] != 0) << 2) | ((u[1] != 0) << 1) | (u[2] != 0);

	switch (dir_code) {
	case 0:
		m = Matrix4::identity();
		break;
	case 4:
		if (u[0] < 0) angle = -angle;
		m = Matrix4::rotation(angle,0);
		break;
	case 2:
		if (u[1] < 0) angle = -angle;
		m = Matrix4::rotation(angle,1);
		break;
	case 1:
		if (u[2] < 0) angle = -angle;
		m = Matrix4::rotation(angle,2);
		break;
	default:
		{
			float cost, sint;

			// normalize vector
			float len = u[0] * u[0] + u[1] * u[1] + u[2] * u[2];
			if (len == 0.0f)
				return;
			len = 1.0f / sqrt(len);
			u[0] *= len;
			u[1] *= len;
			u[2] *= len;

			// store cos and sin values
			cost = cos(angle);
			sint = sin(angle);

			// fill in the values
			m.set(3,0,0.0f);
			m.set(3,1,0.0f);
			m.set(3,2,0.0f);
			m.set(0,3,0.0f);
			m.set(1,3,0.0f);
			m.set(2,3,0.0f);
			m.set(3,3,1.0f);

			// do the math
			m.set(0,0, u[0] * u[0] + cost * (1 - u[0] * u[0]));
			m.set(1,0, u[0] * u[1] * (1 -cost) - u[2] * sint);
			m.set(2,0, u[2] * u[0] * (1 -cost) + u[1] * sint);
			m.set(0,1, u[0] * u[1] * (1 -cost) + u[2] * sint);
			m.set(1,1, u[1] * u[1] + cost * (1 - u[1] * u[1]));
			m.set(2,1, u[1] * u[2] * (1 - cost) - u[0] * sint);
			m.set(0,2, u[2] * u[0] * (1 - cost) - u[1] * sint);
			m.set(1,2, u[1] * u[2] * (1 - cost) + u[0] * sint);
			m.set(2,2, u[2] * u[2] + cost * (1 - u[2] * u[2]));
		}
	}

	*c->matrix_stack_ptr[c->matrix_mode] = (*c->matrix_stack_ptr[c->matrix_mode]) * m;

	gl_matrix_update(c);
}

void glopScale(GLContext *c, GLParam *p) {
	float x = p[1].f, y = p[2].f, z = p[3].f;

	Matrix4 m = Matrix4::identity();

	m.set(0,0,x);
	m.set(1,1,y);
	m.set(2,2,z);

	*c->matrix_stack_ptr[c->matrix_mode] = (*c->matrix_stack_ptr[c->matrix_mode]) * m;

	gl_matrix_update(c);
}

void glopTranslate(GLContext *c, GLParam *p) {
	Matrix4 m = Matrix4::identity();
	float x = p[1].f, y = p[2].f, z = p[3].f;

	m.set(3,0,x);
	m.set(3,1,y);
	m.set(3,2,z);

	*c->matrix_stack_ptr[c->matrix_mode] = (*c->matrix_stack_ptr[c->matrix_mode]) * m;

	gl_matrix_update(c);
}

void glopFrustum(GLContext *c, GLParam *p) {
	Matrix4 m;
	float left = p[1].f;
	float right = p[2].f;
	float bottom = p[3].f;
	float top = p[4].f;
	float nearp = p[5].f;
	float farp = p[6].f;
	float x, y, A, B, C, D;

	x = (float)((2.0 * nearp) / (right - left));
	y = (float)((2.0 * nearp) / (top - bottom));
	A = (right + left) / (right - left);
	B = (top + bottom) / (top - bottom);
	C = -(farp + nearp) / (farp - nearp);
	D = (float)(-(2.0 * farp * nearp) / (farp - nearp));

	m.set(0,0, x); m.set(1,0, 0); m.set(2,0, A);  m.set(3,0, 0);
	m.set(0,1, 0); m.set(1,1, y); m.set(2,1, B);  m.set(3,1, 0);
	m.set(0,2, 0); m.set(1,2, 0); m.set(2,2, C);  m.set(3,2, D);
	m.set(0,3, 0); m.set(1,3, 0); m.set(2,3, -1); m.set(3,3, 0);

	*c->matrix_stack_ptr[c->matrix_mode] = (*c->matrix_stack_ptr[c->matrix_mode]) * m;

	gl_matrix_update(c);
}

} // end of namespace TinyGL