+++ /dev/null
-/*
- * matrix.c
- *
- * Some useful matrix functions.
- *
- * Brian Paul
- * 10 Feb 2004
- */
-
-
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <math.h>
-
-
-/**
- * Pretty-print the given matrix.
- */
-void
-PrintMatrix(const float p[16])
-{
- printf("[ %6.3f %6.3f %6.3f %6.3f ]\n", p[0], p[4], p[8], p[12]);
- printf("[ %6.3f %6.3f %6.3f %6.3f ]\n", p[1], p[5], p[9], p[13]);
- printf("[ %6.3f %6.3f %6.3f %6.3f ]\n", p[2], p[6], p[10], p[14]);
- printf("[ %6.3f %6.3f %6.3f %6.3f ]\n", p[3], p[7], p[11], p[15]);
-}
-
-
-/**
- * Build a glFrustum matrix.
- */
-void
-Frustum(float left, float right, float bottom, float top, float nearZ, float farZ, float *m)
-{
- float x = (2.0F*nearZ) / (right-left);
- float y = (2.0F*nearZ) / (top-bottom);
- float a = (right+left) / (right-left);
- float b = (top+bottom) / (top-bottom);
- float c = -(farZ+nearZ) / ( farZ-nearZ);
- float d = -(2.0F*farZ*nearZ) / (farZ-nearZ);
-
-#define M(row,col) m[col*4+row]
- M(0,0) = x; M(0,1) = 0.0F; M(0,2) = a; M(0,3) = 0.0F;
- M(1,0) = 0.0F; M(1,1) = y; M(1,2) = b; M(1,3) = 0.0F;
- M(2,0) = 0.0F; M(2,1) = 0.0F; M(2,2) = c; M(2,3) = d;
- M(3,0) = 0.0F; M(3,1) = 0.0F; M(3,2) = -1.0F; M(3,3) = 0.0F;
-#undef M
-}
-
-
-/**
- * Build a glOrtho marix.
- */
-void
-Ortho(float left, float right, float bottom, float top, float nearZ, float farZ, float *m)
-{
-#define M(row,col) m[col*4+row]
- M(0,0) = 2.0F / (right-left);
- M(0,1) = 0.0F;
- M(0,2) = 0.0F;
- M(0,3) = -(right+left) / (right-left);
-
- M(1,0) = 0.0F;
- M(1,1) = 2.0F / (top-bottom);
- M(1,2) = 0.0F;
- M(1,3) = -(top+bottom) / (top-bottom);
-
- M(2,0) = 0.0F;
- M(2,1) = 0.0F;
- M(2,2) = -2.0F / (farZ-nearZ);
- M(2,3) = -(farZ+nearZ) / (farZ-nearZ);
-
- M(3,0) = 0.0F;
- M(3,1) = 0.0F;
- M(3,2) = 0.0F;
- M(3,3) = 1.0F;
-#undef M
-}
-
-
-/**
- * Decompose a projection matrix to determine original glFrustum or
- * glOrtho parameters.
- */
-void
-DecomposeProjection( const float *m,
- int *isPerspective,
- float *leftOut, float *rightOut,
- float *botOut, float *topOut,
- float *nearOut, float *farOut)
-{
- if (m[15] == 0.0) {
- /* perspective */
- float p[16];
- const float x = m[0]; /* 2N / (R-L) */
- const float y = m[5]; /* 2N / (T-B) */
- const float a = m[8]; /* (R+L) / (R-L) */
- const float b = m[9]; /* (T+B) / (T-B) */
- const float c = m[10]; /* -(F+N) / (F-N) */
- const float d = m[14]; /* -2FN / (F-N) */
-
- /* These equations found with simple algebra, knowing the arithmetic
- * use to set up a typical perspective projection matrix in OpenGL.
- */
- const float nearZ = -d / (1.0 - c);
- const float farZ = (c - 1.0) * nearZ / (c + 1.0);
- const float left = nearZ * (a - 1.0) / x;
- const float right = 2.0 * nearZ / x + left;
- const float bottom = nearZ * (b - 1.0) / y;
- const float top = 2.0 * nearZ / y + bottom;
-
- *isPerspective = 1;
- *leftOut = left;
- *rightOut = right;
- *botOut = bottom;
- *topOut = top;
- *nearOut = nearZ;
- *farOut = farZ;
- }
- else {
- /* orthographic */
- const float x = m[0]; /* 2 / (R-L) */
- const float y = m[5]; /* 2 / (T-B) */
- const float z = m[10]; /* -2 / (F-N) */
- const float a = m[12]; /* -(R+L) / (R-L) */
- const float b = m[13]; /* -(T+B) / (T-B) */
- const float c = m[14]; /* -(F+N) / (F-N) */
- /* again, simple algebra */
- const float right = -(a - 1.0) / x;
- const float left = right - 2.0 / x;
- const float top = -(b - 1.0) / y;
- const float bottom = top - 2.0 / y;
- const float farZ = (c - 1.0) / z;
- const float nearZ = farZ + 2.0 / z;
-
- *isPerspective = 0;
- *leftOut = left;
- *rightOut = right;
- *botOut = bottom;
- *topOut = top;
- *nearOut = nearZ;
- *farOut = farZ;
- }
-}
-
-
-#if 0
-/* test harness */
-int
-main(int argc, char *argv[])
-{
- float m[16], p[16];
- float l, r, b, t, n, f;
- int persp;
- int i;
-
-#if 0
- l = -.9;
- r = 1.2;
- b = -0.5;
- t = 1.4;
- n = 30;
- f = 84;
- printf(" Frustum(%f, %f, %f, %f, %f, %f\n",l+1, r+1.2, b+.5, t+.3, n, f);
- Frustum(l+1, r+1.2, b+.5, t+.3, n, f, p);
- DecomposeProjection(p, &persp, &l, &r, &b, &t, &n, &f);
- printf("glFrustum(%f, %f, %f, %f, %f, %f)\n",
- l, r, b, t, n, f);
- PrintMatrix(p);
-#else
- printf("Ortho(-1, 1, -1, 1, 10, 84)\n");
- Ortho(-1, 1, -1, 1, 10, 84, m);
- PrintMatrix(m);
- DecomposeProjection(m, &persp, &l, &r, &b, &t, &n, &f);
- printf("Ortho(%f, %f, %f, %f, %f, %f) %d\n", l, r, b, t, n, f, persp);
-#endif
-
- return 0;
-}
-#endif
projects / mesa.git / blobdiff