From fee98162a6a1639a46d5724370bef564c6799a9b Mon Sep 17 00:00:00 2001
From: Allanis <allanis@saracraft.net>
Date: Sat, 1 Jun 2013 21:59:08 +0100
Subject: [PATCH] [Fix] OpenGL blitting stuff.

---
 src/opengl.c | 115 ++++++++++++++++++++++++++++++---------------------
 src/opengl.h |   9 +++-
 2 files changed, 76 insertions(+), 48 deletions(-)

diff --git a/src/opengl.c b/src/opengl.c
index 5759c3f..0e9d8dd 100644
--- a/src/opengl.c
+++ b/src/opengl.c
@@ -32,6 +32,9 @@ static uint8_t* SDL_MapTrans(SDL_Surface* s);
 static int pot(int n);
 // glTexture.
 static GLuint gl_loadSurface(SDL_Surface* surface, int* rw, int* rh);
+static void gl_blitTexture(const glTexture* texture,
+    const double x, const double y,
+    const double tx, const double ty, const glColour* c);
 
 // PNG.
 int write_png(const char* file_name, png_bytep* rows, int w, int h,
@@ -350,82 +353,102 @@ void gl_getSpriteFromDir(int* x, int* y, const glTexture* t, const double dir) {
 // BLITTING!
 // ================
 
+static void gl_blitTexture(const glTexture* texture,
+    const double x, const double y,
+    const double tx, const double ty, const glColour* c) {
+
+  double tw, th;
+
+  // Texture dimensions.
+  tw = texture->sw / texture->rw;
+  th = texture->sh / texture->rh;
+
+  glEnable(GL_TEXTURE_2D);
+  glBindTexture(GL_TEXTURE_2D, texture->texture);
+  glBegin(GL_QUADS);
+    // Set colour or default if not set.
+    if(c == NULL) glColor4d(1., 1., 1., 1.);
+    else COLOUR(*c);
+
+    glTexCoord2d(tx, ty);
+    glVertex2d(x, y);
+
+    glTexCoord2d(tx + tw, ty);
+    glVertex2d(x + texture->sw, y);
+
+    glTexCoord2d(tx + tw, ty + th);
+    glVertex2d(x + texture->sw, y + texture->sh);
+
+    glTexCoord2d(tx, ty + th);
+    glVertex2d(x, y + texture->sh);
+  glEnd();
+  glDisable(GL_TEXTURE_2D);
+
+  // Did anything fail?
+  gl_checkErr();
+}
+
 // Blit the sprite at given position.
 void gl_blitSprite(const glTexture* sprite, const double bx, const double by,
                    const int sx, const int sy, const glColour* c) {
 
-  // Don't bother drawing if offscreen -- waste of cycles.
-  if(fabs(bx-VX(*gl_camera)+gui_xoff) > SCREEN_W / 2 + sprite->sw / 2 ||
-     fabs(by-VY(*gl_camera)+gui_yoff) > SCREEN_H / 2 + sprite->sh / 2)
-    return;
-
   double x, y, tx, ty;
 
-  glEnable(GL_TEXTURE_2D);
-
+  // Calculate position - we'll use relative coords to player.
   x = bx - VX(*gl_camera) - sprite->sw/2. + gui_xoff;
   y = by - VY(*gl_camera) - sprite->sh/2. + gui_yoff;
 
+  // Don't draw if offscreen.
+  if((fabs(x) > SCREEN_W/2 + sprite->sw) ||
+      (fabs(y) > SCREEN_H/2 + sprite->sh))
+    return;
+
+  // Texture coords.
   tx = sprite->sw * (double)(sx)/sprite->rw;
   ty = sprite->sh * (sprite->sy-(double)sy-1)/sprite->rh;
 
-  // Actual blitting....
-  glBindTexture(GL_TEXTURE_2D, sprite->texture);
-  glBegin(GL_QUADS);
-  if(c == NULL) glColor4d(1., 1., 1., 1.);
-  else COLOUR(*c);
+  // Actual blitting.
+  gl_blitTexture(sprite, x, y, tx, ty, c);
+}
 
-  glTexCoord2d(tx, ty);
-  glVertex2d(x, y);
+// Like gl_blitSprite but will use the actual direction, for things that
+// can just rotate around.
+void gl_blitRotate(const glTexture* texture,
+    const double bx, const double by,
+    const double dir, const glColour* c) {
 
-  glTexCoord2d(tx + sprite->sw/sprite->rw, ty);
-  glVertex2d(x + sprite->sw, y);
+  double x, y;
 
-  glTexCoord2d(tx + sprite->sw/sprite->rw, ty + sprite->sh/sprite->rh);
-  glVertex2d(x + sprite->sw, y + sprite->sh);
+  // Calculate position - we'll use relative coords to player.
+  x = bx - VX(*gl_camera) - texture->sw/2. + gui_xoff;
+  y = by - VY(*gl_camera) - texture->sh/2. + gui_yoff;
 
-  glTexCoord2d(tx, ty + sprite->sh/sprite->rh);
-  glVertex2d(x, y + sprite->sh);
+  // Don't draw if offscreen.
+  if((fabs(x) > SCREEN_W/2 + texture->sw) ||
+      (fabs(y) > SCREEN_H/2 + texture->sh))
+    return;
 
-  glEnd();
+  glMatrixMode(GL_PROJECTION);
+  glPushMatrix();
+  glRotated(dir, 0., 0., 1.);
 
-  glDisable(GL_TEXTURE_2D);
+  // Blit.
+  gl_blitTexture(texture, x, y, 0, 0, c);
 
-  gl_checkErr();
+  glPopMatrix(); // GL_PROJECTION.
 }
 
 // Just straight out blit the thing at position.
 void gl_blitStatic(const glTexture* texture, const double bx, const double by,
                    const glColour* c) {
   double x, y;
-  glEnable(GL_TEXTURE_2D);
 
+  // Here we use absolute coords.
   x = bx - (double)SCREEN_W/2.;
   y = by - (double)SCREEN_H/2.;
 
   // Actual blitting..
-  glBindTexture(GL_TEXTURE_2D, texture->texture);
-  glBegin(GL_QUADS);
-  if(c == NULL) glColor4d(1., 1., 1., 1.);
-  else COLOUR(*c);
-
-  glTexCoord2d(0., 0.);
-  glVertex2d(x, y);
-
-  glTexCoord2d(texture->sw/texture->rw, 0.);
-  glVertex2d(x + texture->sw, y);
-
-  glTexCoord2d(texture->sw/texture->rw, texture->sh/texture->rh);
-  glVertex2d(x + texture->sw, y + texture->sh);
-
-  glTexCoord2d(0., texture->sh/texture->rh);
-  glVertex2d(x, y + texture->sh);
-
-  glEnd();
-
-  glDisable(GL_TEXTURE_2D);
-
-  gl_checkErr();
+  gl_blitTexture(texture, x, y, 0, 0, c);
 }
 
 // Bind our precious camera to a vector.
diff --git a/src/opengl.h b/src/opengl.h
index d03b41b..1d5b4c6 100644
--- a/src/opengl.h
+++ b/src/opengl.h
@@ -60,11 +60,16 @@ glTexture* gl_newSprite(const char* path, const int sx, const int sy);
 void gl_freeTexture(glTexture* texture);
 
 // Rendering.
-// Blits a sprite.
+// Blits a sprite, relative pos.
 void gl_blitSprite(const glTexture* sprite, const double bx, const double by,
                    const int sx, const int sy, const glColour* c);
 
-// Blit the entire image.
+// Blits a texture rotated, relative pos.
+void gl_blitRotate(const glTexture* texture,
+    const double bx, const double by,
+    const double dir, const glColour* c);
+
+// Blit the entire image, absolute pos.
 void gl_blitStatic(const glTexture* texture, const double bx, const double by,
                    const glColour* c);