From d1c87b38ac982e6197193e3999da18d4c9891ad9 Mon Sep 17 00:00:00 2001
From: John Alanbrook <john@pockle.world>
Date: Mon, 20 Feb 2023 22:28:07 +0000
Subject: [PATCH] Grid rendering

---
 source/engine/2dphysics.c       | 34 +++++++++++++++------------------
 source/engine/debug/debugdraw.c | 15 ++++++++++++++-
 source/engine/openglrender.c    |  4 +++-
 source/engine/openglrender.h    |  1 +
 source/engine/sprite.c          |  2 +-
 5 files changed, 34 insertions(+), 22 deletions(-)

diff --git a/source/engine/2dphysics.c b/source/engine/2dphysics.c
index 0b26df0..fcf4054 100644
--- a/source/engine/2dphysics.c
+++ b/source/engine/2dphysics.c
@@ -204,8 +204,19 @@ void phys2d_circledel(struct phys2d_circle *c)
 
 cpVect world2go(struct gameobject *go, cpVect worldpos)
 {
-  worldpos = cpvsub(worldpos, cpBodyGetPosition(go->body));
-  worldpos = cpvmult(worldpos, 1/go->scale);
+  cpTransform T = {0};
+  cpVect pos = cpBodyGetPosition(go->body);
+  worldpos.x -= pos.x;
+  worldpos.y -= pos.y;
+//  worldpos.x /= go->scale;
+//  worldpos.y /= go->scale;
+  float angle = cpBodyGetAngle(go->body);
+  T.a = go->flipx * cos(-angle) / go->scale;
+  T.b = sin(-angle) / go->scale;
+  T.c = -sin(-angle) / go->scale;
+  T.d = go->flipy * cos(-angle) / go->scale;
+  worldpos = cpTransformPoint(T,worldpos);
+
   return worldpos;
 }
 
@@ -215,29 +226,14 @@ cpVect go2world(struct gameobject *go, cpVect gopos)
   float angle = cpBodyGetAngle(go->body);
   cpTransform T = {0};
   T.a = go->scale * go->flipx * cos(angle);
-  T.b = -sin(angle) * go->scale;
-  T.c = sin(angle) * go->scale;
+  T.b = sin(angle) * go->scale * go->flipx;
+  T.c = -sin(angle) * go->scale * go->flipy;
   T.d = go->scale * go->flipy * cos(angle);
   T.tx = pos.x;
   T.ty = pos.y;
   return cpTransformPoint(T, gopos);
 }
 
-cpTransform body2transform(cpBody *body)
-{
-  cpTransform T = {0};
-  cpVect pos = cpBodyGetPosition(body);
-  float angle = cpBodyGetAngle(body);
-  T.a = cos(angle);
-  T.b = -sin(angle);
-  T.c = sin(angle);
-  T.d = cos(angle);
-  T.tx = pos.x;
-  T.ty = pos.y;
-  
-  return T;
-}
-
 cpVect gotransformpoint(struct gameobject *go, cpVect point)
 {
   point.x *= go->scale * go->flipx;
diff --git a/source/engine/debug/debugdraw.c b/source/engine/debug/debugdraw.c
index 6d40d02..c06648e 100644
--- a/source/engine/debug/debugdraw.c
+++ b/source/engine/debug/debugdraw.c
@@ -241,8 +241,10 @@ void draw_grid(int width, int span)
     shader_setint(gridShader, "span", span);
     
     cpVect offset = cam_pos();
+        offset = cpvmult(offset, 1/cam_zoom());
     offset.x -= mainwin->width/2;
     offset.y -= mainwin->height/2;
+
     shader_setvec2(gridShader, "offset", &offset);
     
     glBindVertexArray(gridVAO);
@@ -251,7 +253,18 @@ void draw_grid(int width, int span)
 
 void draw_point(int x, int y, float r, float *color)
 {
-    draw_circle(x, y, r, r, color, 0);
+    shader_use(circleShader);
+
+    float verts[] = { x, y };
+
+    glBindBuffer(GL_ARRAY_BUFFER, circleVBO);
+    glBufferData(GL_ARRAY_BUFFER, sizeof(verts), verts, GL_DYNAMIC_DRAW);
+    glPointSize(r);
+
+    glBindVertexArray(circleVAO);
+    glEnableVertexAttribArray(0);
+    glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 0, NULL);
+    glDrawArrays(GL_POINTS, 0, 4);
 }
 
 void draw_cppoint(struct cpVect point, float r)
diff --git a/source/engine/openglrender.c b/source/engine/openglrender.c
index 1a52f44..53f473e 100644
--- a/source/engine/openglrender.c
+++ b/source/engine/openglrender.c
@@ -118,8 +118,10 @@ void set_cam_body(cpBody *body) {
 cpVect cam_pos() {
     return camera ? cpBodyGetPosition(camera) : cpvzero;
 }
-
 static float zoom = 1.f;
+float cam_zoom() { return zoom; }
+
+
 void add_zoom(float val) { zoom = val; }
 
 void openglRender(struct window *window)
diff --git a/source/engine/openglrender.h b/source/engine/openglrender.h
index 151bafb..f52c70e 100644
--- a/source/engine/openglrender.h
+++ b/source/engine/openglrender.h
@@ -51,6 +51,7 @@ void BindUniformBlock(GLuint shaderID, const char *bufferName, GLuint bufferBind
 
 void set_cam_body(cpBody *body);
 cpVect cam_pos();
+float cam_zoom();
 void add_zoom(float val);
 
 #endif
diff --git a/source/engine/sprite.c b/source/engine/sprite.c
index 4c9762e..f313329 100644
--- a/source/engine/sprite.c
+++ b/source/engine/sprite.c
@@ -137,7 +137,7 @@ void tex_draw(struct Texture *tex, float pos[2], float angle, float size[2], flo
 
 	mat4_translate_vec2(model, t_offset);
 
-mat4_scale_vec2(model, t_scale);
+        mat4_scale_vec2(model, t_scale);
 	mat4_rotation_z(r_model, angle);
 
 	mat4_multiply(model, r_model, model);