From d4f20c83793e9f9068f0e50e93c60e7b141a7c3b Mon Sep 17 00:00:00 2001
From: bjorn <tie.372@gmail.com>
Date: Thu, 29 Sep 2016 19:39:25 -0700
Subject: [PATCH] lovr.graphics.line;

---
 src/graphics/graphics.c |  9 +++++++--
 src/graphics/graphics.h |  6 ++++++
 src/lovr/graphics.c     | 36 ++++++++++++++++++++++++++++++++++++
 src/lovr/graphics.h     |  1 +
 4 files changed, 50 insertions(+), 2 deletions(-)

diff --git a/src/graphics/graphics.c b/src/graphics/graphics.c
index 3e6cf5e5..dc5a1a3a 100644
--- a/src/graphics/graphics.c
+++ b/src/graphics/graphics.c
@@ -243,11 +243,16 @@ void lovrGraphicsSetShapeData(float* data, int count) {
   glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, NULL);
 }
 
-void lovrGraphicsDrawShape() {
+void lovrGraphicsDrawShape(DrawMode mode) {
   lovrGraphicsPrepare();
   glBindVertexArray(state.shapeArray);
   glEnableVertexAttribArray(0);
-  glDrawArrays(GL_TRIANGLE_FAN, 0, state.shapeData.length / 3);
+  glDrawArrays(mode, 0, state.shapeData.length / 3);
+}
+
+void lovrGraphicsLine(float* points, int count) {
+  lovrGraphicsSetShapeData(points, count);
+  lovrGraphicsDrawShape(DRAW_MODE_LINE);
 }
 
 Buffer* lovrGraphicsNewBuffer(int size, BufferDrawMode drawMode, BufferUsage usage) {
diff --git a/src/graphics/graphics.h b/src/graphics/graphics.h
index 0af9ca00..7fd1f936 100644
--- a/src/graphics/graphics.h
+++ b/src/graphics/graphics.h
@@ -20,6 +20,11 @@ typedef struct {
   int height;
 } ScissorRectangle;
 
+typedef enum {
+  DRAW_MODE_FILL = GL_TRIANGLE_FAN,
+  DRAW_MODE_LINE = GL_LINE_STRIP
+} DrawMode;
+
 typedef struct {
   Shader* activeShader;
   Shader* defaultShader;
@@ -67,6 +72,7 @@ void lovrGraphicsTransform(mat4 transform);
 void lovrGraphicsGetDimensions(int* width, int* height);
 void lovrGraphicsSetShapeData(float* data, int count);
 void lovrGraphicsDrawShape();
+void lovrGraphicsLine(float* points, int count);
 Buffer* lovrGraphicsNewBuffer(int size, BufferDrawMode drawMode, BufferUsage usage);
 Model* lovrGraphicsNewModel(const char* path);
 Shader* lovrGraphicsNewShader(const char* vertexSource, const char* fragmentSource);
diff --git a/src/lovr/graphics.c b/src/lovr/graphics.c
index 11116f00..d94ab1ae 100644
--- a/src/lovr/graphics.c
+++ b/src/lovr/graphics.c
@@ -25,6 +25,7 @@ const luaL_Reg lovrGraphics[] = {
   { "translate", l_lovrGraphicsTranslate },
   { "rotate", l_lovrGraphicsRotate },
   { "scale", l_lovrGraphicsScale },
+  { "line", l_lovrGraphicsLine },
   { "getWidth", l_lovrGraphicsGetWidth },
   { "getHeight", l_lovrGraphicsGetHeight },
   { "getDimensions", l_lovrGraphicsGetDimensions },
@@ -244,6 +245,41 @@ int l_lovrGraphicsScale(lua_State* L) {
   return 0;
 }
 
+int l_lovrGraphicsLine(lua_State* L) {
+  vec_float_t points;
+  vec_init(&points);
+  int isTable = lua_istable(L, 1);
+
+  if (!isTable && !lua_isnumber(L, 1)) {
+    return luaL_error(L, "Expected number or table, got '%s'", lua_typename(L, lua_type(L, 1)));
+  }
+
+  int count = isTable ? lua_objlen(L, 1) : lua_gettop(L);
+  if (count % 3 != 0) {
+    vec_deinit(&points);
+    return luaL_error(L, "Number of coordinates must be a multiple of 3, got '%d'", count);
+  }
+
+  vec_reserve(&points, count);
+
+  if (isTable) {
+    for (int i = 1; i <= count; i++) {
+      lua_rawgeti(L, 1, i);
+      vec_push(&points, lua_tonumber(L, -1));
+      lua_pop(L, 1);
+    }
+  } else {
+    for (int i = 1; i <= count; i++) {
+      vec_push(&points, lua_tonumber(L, i));
+    }
+  }
+
+  lovrGraphicsSetShapeData(points.data, count);
+  lovrGraphicsDrawShape(DRAW_MODE_LINE);
+  vec_deinit(&points);
+  return 0;
+}
+
 int l_lovrGraphicsGetWidth(lua_State* L) {
   int width;
   lovrGraphicsGetDimensions(&width, NULL);
diff --git a/src/lovr/graphics.h b/src/lovr/graphics.h
index c11a6b67..a776bb88 100644
--- a/src/lovr/graphics.h
+++ b/src/lovr/graphics.h
@@ -28,6 +28,7 @@ int l_lovrGraphicsOrigin(lua_State* L);
 int l_lovrGraphicsTranslate(lua_State* L);
 int l_lovrGraphicsRotate(lua_State* L);
 int l_lovrGraphicsScale(lua_State* L);
+int l_lovrGraphicsLine(lua_State* L);
 int l_lovrGraphicsGetWidth(lua_State* L);
 int l_lovrGraphicsGetHeight(lua_State* L);
 int l_lovrGraphicsGetDimensions(lua_State* L);