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] *= 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] *= 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 = c->matrix_stack_ptr[c->matrix_mode];

	m->set(0, 0, m->get(0, 0) * x); m->set(0, 1, m->get(0, 1) * y); m->set(0, 2, m->get(0, 2) * z);
	m->set(1, 0, m->get(1, 0) * x); m->set(1, 1, m->get(1, 1) * y); m->set(1, 2, m->get(1, 2) * z);
	m->set(2, 0, m->get(2, 0) * x); m->set(2, 1, m->get(2, 1) * y); m->set(2, 2, m->get(2, 2) * z);
	m->set(3, 0, m->get(3, 0) * x); m->set(3, 1, m->get(3, 1) * y); m->set(3, 2, m->get(3, 2) * z);

	gl_matrix_update(c);
}

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

	Matrix4 *m = c->matrix_stack_ptr[c->matrix_mode];

	m->set(0, 3, m->get(0,0) * x + m->get(0,1) * y + m->get(0,2) * z + m->get(0,3));
	m->set(1, 3, m->get(1,0) * x + m->get(1,1) * y + m->get(1,2) * z + m->get(1,3));
	m->set(2, 3, m->get(2,0) * x + m->get(2,1) * y + m->get(2,2) * z + m->get(2,3));
	m->set(3, 3, m->get(3,0) * x + m->get(3,1) * y + m->get(3,2) * z + m->get(3,3));

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

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

	gl_matrix_update(c);
}

} // end of namespace TinyGL