Diff: gfx3d.cpp

Revision:

0:215c9308dc52

Child:

1:f346d04ccbad

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gfx3d.cpp	Sun Oct 25 11:26:02 2015 +0000
@@ -0,0 +1,117 @@
+/*
+ *  gfx3d.cpp -- 3D stuff for MBED (just playing!)
+ *  Copyright (C) 2015 Fred Barnes, University of Kent  <frmb@kent.ac.uk>
+ */
+
+/** @file gfx3d.cpp */
+
+/** gfx3d library
+ *
+ *  This is a library for primitive 3D graphics.  No classes, just C functions.
+ */
+ 
+
+#include "mbed.h"
+#include "C12832.h"
+#include "gfx3d.h"
+
+
+/**
+ *  rotates a base set of points into a new set (demoscene style)
+ */
+void gfx3d_rotate_demo (const g3d_p3_t *src, g3d_p3_t *dst, const int npnts, const angle_t a)
+{
+    float sinval = gfx3d_sin (a);
+    float cosval = gfx3d_cos (a);
+    int i;
+    
+    for (i=0; i<npnts; i++) {
+        float x1 = (src[i].x * cosval) + (src[i].y * sinval);
+        float y1 = (src[i].y * cosval) - (src[i].x * sinval);
+        float z1 = (src[i].z * cosval) - (x1 * sinval);
+        float t;
+        
+        dst[i].x = (x1 * cosval) + (src[i].z * sinval);
+        t = (y1 * cosval) + (z1 * sinval);
+        dst[i].z = (z1 * cosval) - (y1 * sinval);
+        dst[i].y = t;
+    }
+    
+}
+
+
+/*
+ *  translates a set of 3D points.  'src' and 'dst' can be the same
+ */
+void gfx3d_translate (const g3d_p3_t *src, g3d_p3_t *dst, const int npnts, const g3d_p3_t tx)
+{
+    int i;
+    
+    if (tx.x != 0.0f) {
+        for (i=0; i<npnts; i++) {
+            dst[i].x = src[i].x + tx.x;
+        }
+    } else if (src != dst) {
+        for (i=0; i<npnts; i++) {
+            dst[i].x = src[i].x;
+        }
+    }
+    if (tx.y != 0.0f) {
+        for (i=0; i<npnts; i++) {
+            dst[i].y = src[i].y + tx.y;
+        }
+    } else if (src != dst) {
+        for (i=0; i<npnts; i++) {
+            dst[i].y = src[i].y;
+        }
+    }
+    if (tx.z != 0.0f) {
+        for (i=0; i<npnts; i++) {
+            dst[i].z = src[i].z + tx.z;
+        }
+    } else if (src != dst) {
+        for (i=0; i<npnts; i++) {
+            dst[i].z = src[i].z;
+        }
+    }
+}
+
+
+/*
+ *  projects a set of 3D points into a 2D space (pretty crude)
+ */
+void gfx3d_project (const g3d_p3_t *src, g3d_2p3_t *dst, const int npnts)
+{
+    int i;
+    
+    for (i=0; i<npnts; i++) {
+        float ez = src[i].z;
+        
+        dst[i].z = (int)(ez * G3D_ZBSCALE) + G3D_ZBADD;
+        ez += G3D_Z_DEPTH;
+        dst[i].x = (int)((src[i].x / ez) * G3D_X_SCALE) + G3D_X2_SHIFT;
+        dst[i].y = (int)((src[i].y / ez) * G3D_Y_SCALE) + G3D_Y2_SHIFT;
+    }
+}
+
+
+/*
+ *  takes a set of 8 projected points and draws a wireframe cube on the given LCD.  FIXME: only interested in the buffer ops..
+ */
+void gfx3d_wirecube (const g3d_2p3_t *src, C12832 &lcd)
+{
+    lcd.line (src[0].x, src[0].y, src[1].x, src[1].y, 1);
+    lcd.line (src[1].x, src[1].y, src[2].x, src[2].y, 1);
+    lcd.line (src[2].x, src[2].y, src[3].x, src[3].y, 1);
+    lcd.line (src[3].x, src[3].y, src[0].x, src[0].y, 1);
+    
+    lcd.line (src[4].x, src[4].y, src[5].x, src[5].y, 1);
+    lcd.line (src[5].x, src[5].y, src[6].x, src[6].y, 1);
+    lcd.line (src[6].x, src[6].y, src[7].x, src[7].y, 1);
+    lcd.line (src[7].x, src[7].y, src[4].x, src[4].y, 1);
+
+    lcd.line (src[0].x, src[0].y, src[4].x, src[4].y, 1);
+    lcd.line (src[1].x, src[1].y, src[5].x, src[5].y, 1);
+    lcd.line (src[2].x, src[2].y, src[6].x, src[6].y, 1);
+    lcd.line (src[3].x, src[3].y, src[7].x, src[7].y, 1);
+}
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