begin 3D rendering, basic camera controlsHEADmaster

1 files changed, 214 insertions, 0 deletions

diff --git a/src/graphics33.c b/src/graphics33.c
new file mode 100644
index 0000000..686aa86
--- /dev/null
+++ b/src/graphics33.c
@@ -0,0 +1,214 @@
+#include "math.h"
+
+#include "options33.h"
+#include "types33.h"
+#include "display33.h"
+#include "scene33.h"
+#include "strings33.h"
+#include "logger33.h"
+
+
+#define _FOV_HALF (0.78539816339744830962/2.0)
+#define _NEAR 1.0
+#define _FAR 24.0
+
+
+static Mat4 _projectionMatrix = {0,};
+static Mat4 _viewMatrix;
+static Mat4 _worldMatrix;
+static f64 _preXformedModelVertices[ E33_VERTICES_PER_MODEL_MAX ][4];
+
+
+static void _draw_line( Vec2 v0, Vec2 v1, u32 colour );
+
+
+Error graphics33_init( void )
+{
+  f64 ar, cot;
+  f64 displayW = (f64)__display.surface.w;
+  f64 displayH = (f64)__display.surface.h;
+
+  ar = displayW / displayH;
+  cot = 1.0 / tan( _FOV_HALF );
+
+  _projectionMatrix[ 0] = cot / ar;
+  _projectionMatrix[ 5] = cot;
+  _projectionMatrix[10] = _FAR / (_FAR - _NEAR);
+  _projectionMatrix[11] = 1.0;
+  _projectionMatrix[14] = -_NEAR * (_FAR / (_FAR - _NEAR));
+
+
+  return E33_EXIT_SUCCESS;
+}
+
+Error graphics33_term( void )
+{
+  return E33_EXIT_SUCCESS;
+}
+
+void graphics33_update( void )
+{
+  math33_create_view_matrix(__scene.camera.t, __scene.camera.r, _viewMatrix );
+  VxP( _viewMatrix, _projectionMatrix );
+}
+
+void graphics33_decompose_scene( void )
+{
+  extern Scene33 __scene;
+
+  Size i, j;
+  Size displayW = __display.surface.w;
+  Size displayH = __display.surface.h;
+  Model33 *model = &__scene.cube;
+
+  ModelEdge33 *medges = model->medges;
+  Size *sedges = model->sedges;
+
+  Size modelVertexCount = model->vertexCount;
+  Size modelSurfaceCount = model->surfaceCount;
+
+
+  math33_create_world_matrix( model->t, model->r, model->s, _worldMatrix );
+  MxM4( _worldMatrix, _viewMatrix );
+
+  #define pV _preXformedModelVertices
+  for( i = 0; i < modelVertexCount; ++i ) {
+    f64 iw;
+
+    V4xMt( pV[i], model->vertices[i], _worldMatrix );
+
+    iw = 1.0 / pV[i][3];
+    pV[i][0] = ( ((pV[i][0] * iw) + 1.0) * 0.5 );
+    pV[i][1] = ( ((pV[i][1] * iw) + 1.0) * 0.5 );
+  }
+
+  for( i = 0; i < modelSurfaceCount; ++i )
+  {
+    Vec4 v[16];
+    Size a[2], b[2], c[2];
+    Boolean needsClippage = 0;
+
+    a[0] = medges[ sedges[i*3  ] ].vertices[0];
+    a[1] = medges[ sedges[i*3  ] ].vertices[1];
+    b[0] = medges[ sedges[i*3+1] ].vertices[0];
+    b[1] = medges[ sedges[i*3+1] ].vertices[1];
+    c[0] = medges[ sedges[i*3+2] ].vertices[0];
+    c[1] = medges[ sedges[i*3+2] ].vertices[1];
+
+    if( a[0] == b[0] )
+    {
+      Size tmp = a[0];
+      a[0] = a[1];
+      a[1] = tmp;
+    }
+    else if( a[1] == b[1] )
+    {
+      Size tmp = b[0];
+      b[0] = b[1];
+      b[1] = tmp;
+    }
+
+    if( c[1] != a[0] ) {
+      Size tmp = c[0];
+      c[0] = c[1];
+      c[1] = tmp;
+    }
+
+    if( ( (pV[a[0]][0] - pV[b[0]][0]) * (pV[c[0]][1] - pV[b[0]][1]) - 
+          (pV[a[0]][1] - pV[b[0]][1]) * (pV[c[0]][0] - pV[b[0]][0]) ) <= 0 ) {
+      continue;
+    }
+
+    v[0][3] = pV[a[0]][3];
+    if( v[0][3] <= _NEAR ) continue;
+    if( v[0][3] > _FAR ) continue;
+    v[0][0] = pV[a[0]][0];
+    v[0][1] = pV[a[0]][1];
+    v[0][2] = pV[a[0]][2];
+
+    v[1][3] = pV[b[0]][3];
+    if( v[1][3] <= _NEAR ) continue;
+    if( v[1][3] > _FAR ) continue;
+    v[1][0] = pV[b[0]][0];
+    v[1][1] = pV[b[0]][1];
+    v[1][2] = pV[b[0]][2];
+
+    v[2][3] = pV[c[0]][3];
+    if( v[2][3] <= _NEAR ) continue;
+    if( v[2][3] > _FAR ) continue;
+    v[2][0] = pV[c[0]][0];
+    v[2][1] = pV[c[0]][1];
+    v[2][2] = pV[c[0]][2];
+
+    v[0][0] *= (f64)(displayW - 1);
+    v[0][1] *= (f64)(displayH - 1);
+    v[1][0] *= (f64)(displayW - 1);
+    v[1][1] *= (f64)(displayH - 1);
+    v[2][0] *= (f64)(displayW - 1);
+    v[2][1] *= (f64)(displayH - 1);
+
+    _draw_line( v[0], v[1], CYAN );
+    _draw_line( v[1], v[2], CYAN );
+    _draw_line( v[2], v[0], CYAN );
+  }
+  #undef pV
+}
+
+
+static void _draw_line( Vec2 v0, Vec2 v1, u32 colour )
+{
+  u32 *dest = __display.surface.data;
+  Size w = __display.surface.w;
+  Size h = __display.surface.h;
+  Size x0 = (Size)(v0[0] + 0.5 );
+  Size y0 = (Size)(v0[1] + 0.5 );
+  Size x1 = (Size)(v1[0] + 0.5 );
+  Size y1 = (Size)(v1[1] + 0.5 );
+
+  Size sx, sy;
+  Size dx, dy, error;
+
+
+  dx = (x1 - x0);
+  if( dx < 0 ) { dx = -dx; }
+  sx = -1; if( x0 < x1 ) sx = 1;
+
+  dy = -(y1 - y0);
+  if( dy > 0 ) { dy = -dy; }
+  sy = -1; if( y0 < y1 ) sy = 1;
+
+  error = dx + dy;
+
+  while( 1 )
+  {
+    Size e2;
+
+    dest[ x0 + y0 * w ] = colour;
+
+    if( (x0 == x1) && (y0 == y1) ) {
+      break;
+    }
+
+    e2 = error << 1;
+
+    if( e2 >= dy )
+    {
+      if( x0 == x1 ) {
+        break;
+      }
+
+      error += dy;
+      x0 += sx;
+    }
+
+    if( e2 <= dx )
+    {
+      if( y0 == y1 ) {
+        break;
+      }
+
+      error += dx;
+      y0 += sy;
+    }
+  }
+}