1 files changed, 71 insertions, 0 deletions
diff --git a/src/video/graphics_utility.c b/src/video/graphics_utility.c
new file mode 100644
index 0000000..5aa3dea
--- /dev/null
+++ b/src/video/graphics_utility.c
@@ -0,0 +1,71 @@
+#include "video/video.h"
+#include "game/game.h"
+
+void checkGLError(const char *where) {
+  int error;
+  error = glGetError();
+  if(error != GL_NO_ERROR)
+    printf("[glError: %s] - %d\n", where, error);
+}
+
+void rasonly(Visual *d) {
+  /* do rasterising only (in local display d) */
+  glMatrixMode(GL_PROJECTION);
+  glLoadIdentity();
+  glOrtho(0.0f, (GLfloat) d->vp_w, 0.0f, (GLfloat) d->vp_h, 0.0f, 1.0f);
+  checkGLError("rasonly");
+  glMatrixMode(GL_MODELVIEW);
+  glLoadIdentity();
+  glViewport(d->vp_x, d->vp_y, d->vp_w, d->vp_h);
+}
+
+
+void doPerspective(float fov, float ratio, float znear, float zfar) {
+  float top;
+  float left;
+
+  top = tanf( fov * PI / 360.0 ) * znear;
+  left = - top * ratio;
+  glFrustum(left, -left, -top, top, znear, zfar);
+}
+
+void doLookAt(float *cam, float *target, float *up) {
+  float m[16];
+  float x[3], y[3], z[3];
+
+  vsub(cam, target, z);
+  normalize(z);
+  crossprod(up, z, x);
+  crossprod(z, x, y);
+  normalize(x);
+  normalize(y);
+
+#define M(row,col)  m[col*4+row]
+  M(0,0) = x[0];  M(0,1) = x[1];  M(0,2) = x[2];  M(0,3) = 0.0;
+  M(1,0) = y[0];  M(1,1) = y[1];  M(1,2) = y[2];  M(1,3) = 0.0;
+  M(2,0) = z[0];  M(2,1) = z[1];  M(2,2) = z[2];  M(2,3) = 0.0;
+  M(3,0) = 0.0;   M(3,1) = 0.0;   M(3,2) = 0.0;   M(3,3) = 1.0;
+#undef M
+  glMultMatrixf( m );
+
+  /* Translate Eye to Origin */
+  glTranslatef( -cam[0], -cam[1], -cam[2]);
+}
+
+void drawText(FontTex* ftx, int x, int y, int size, const char *text) {
+  glEnable(GL_BLEND);
+  glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+  glEnable(GL_TEXTURE_2D);
+
+  glPushMatrix();
+
+  glTranslatef(x, y, 0);
+  glScalef(size, size, size);
+  ftxRenderString(ftx, text, strlen(text));
+  
+  glPopMatrix();
+  glDisable(GL_TEXTURE_2D);
+  glDisable(GL_BLEND);
+  polycount += 2 * strlen(text); /* quads are two triangles */
+}
+