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authormarha <marha@users.sourceforge.net>2009-10-08 13:15:52 +0000
committermarha <marha@users.sourceforge.net>2009-10-08 13:15:52 +0000
commita0c4815433ccd57322f4f7703ca35e9ccfa59250 (patch)
treef5213802ec12adb86ec3136001c1c29fe5343700 /mesalib/progs/util/matrix.c
parentc73dc01b6de45612b24dc2dd34fba24d81ebf46c (diff)
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Added MesaLib-7.6
Diffstat (limited to 'mesalib/progs/util/matrix.c')
-rw-r--r--mesalib/progs/util/matrix.c181
1 files changed, 181 insertions, 0 deletions
diff --git a/mesalib/progs/util/matrix.c b/mesalib/progs/util/matrix.c
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+/*
+ * 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