Start adding some basic collision primitives.

CMakeLists.txt

@@ -18,6 +18,9 @@ add_executable(${PROJECT_NAME}
 	src/texture.d
 	src/gameobjjumping.d
 	src/vector.d
+	src/collisionline.d
+	src/rect.d
+	src/collidingentity.d
 
 	lib/DerelictSDL2/source/derelict/sdl2/functions.d
 	lib/DerelictSDL2/source/derelict/sdl2/image.d

src/collidingentity.d

@@ -0,0 +1,41 @@
+/* Copyright 2015, Michele Santullo
+ * This file is part of "Jumping in D".
+ *
+ * "Jumping in D" is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * "Jumping in D" is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with "Jumping in D".  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+module collidingentity;
+import collisionline;
+
+struct CollidingEntity {
+	@property ref const(CollisionQuad) current() const { return m_current; }
+
+	ref CollidingEntity opOpAssign(string op)(ref const(vec2) parOffset) {
+		static if ("+" == op || "-" == op) {
+			m_offs = parOffset;
+			mixin("m_current.left "~op~"= parOffset;");
+			mixin("m_current.top "~op~"= parOffset;");
+			mixin("m_current.right "~op~"= parOffset;");
+			mixin("m_current.bottom "~op~"= parOffset;");
+			return this;
+		}
+		else {
+			static assert(false, "No CollidingEntity::operator"~op~" available");
+		}
+	}
+
+private:
+	CollisionQuad m_current;
+	vec2 m_offs;
+}

src/collisionline.d

@@ -0,0 +1,65 @@
+/* Copyright 2015, Michele Santullo
+ * This file is part of "Jumping in D".
+ *
+ * "Jumping in D" is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * "Jumping in D" is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with "Jumping in D".  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+module collisionline;
+public import vector : Vector;
+import rect : Rect;
+
+alias vec2 = Vector!(float, 2);
+
+struct CollisionLine {
+	this (in vec2 parA, in vec2 parB) {
+		m_from = parA;
+		m_to = parB;
+		assert(m_from != m_to);
+	}
+
+	@property ref const(vec2) from() const { return m_from; }
+	@property ref const(vec2) to() const { return m_to; }
+
+	//This is how you provide your own operator+= and operator-= in D
+	ref CollisionLine opOpAssign(string op)(ref const(vec2) parOffset) {
+		static if ("+" == op || "-" == op) {
+			mixin("m_from "~op~"= parOffset;");
+			mixin("m_to "~op~"= parOffset;");
+			return this;
+		}
+		else {
+			static assert(false, "No CollisionLine::operator"~op~" available");
+		}
+	}
+
+private:
+	vec2 m_from;
+	vec2 m_to;
+}
+
+struct CollisionQuad {
+	Rect!CollisionLine m_lines;
+
+	//Structs don't have inheritance, but you can achieve the same with:
+	alias m_lines this;
+}
+
+bool collides (CollisionLine parLine, CollisionLine parLine1, vec2 parOffs, out vec2 parPoint) {
+	parPoint = vec2(0.0f);
+	return false;
+}
+
+bool collides (CollisionQuad parQuad, CollisionQuad parQuad1, vec2 parOffs, out vec2 parPoint) {
+	return false;
+}

src/gameobjjumping.d

@@ -20,9 +20,8 @@ public import gameobj;
 import derelict.sdl2.sdl;
 import texture;
 import std.stdio;
-import vector : Vector;
+import collisionline;
-
+import collidingentity : CollidingEntity;
-alias vec2 = Vector!(float, 2);
 
 //This is one possible game scene. It will draw a texture on the screen
 //and it will report user wants to quit if you press the close button in the
@@ -74,6 +73,17 @@ class GameObjJumping : GameObj {
 	//This is the function that is called at every frame. It represents the
 	//main loop's body.
 	override void exec() {
+		//Move the sprite around (note that we store the original position)
+		vec2 offs = vec2(0.0f);
+		m_coll_sprite += offs;
+
+		//Check for collision between our sprite and the screen edges
+		//vec2 collision_point;
+		//if (m_coll_sprite.collides(m_coll_screen, collision_point)) {
+			//assert(false); //not implemented
+		//}
+
+		//Draw the sprite
 		SDL_RenderClear(renderer());
 		m_texture.draw();
 		SDL_RenderPresent(renderer());
@@ -86,6 +96,8 @@ class GameObjJumping : GameObj {
 
 private:
 	Texture m_texture;
+	CollisionQuad m_coll_screen;
+	CollidingEntity m_coll_sprite;
 	bool m_wants_to_quit;
 }
 

src/rect.d

@@ -0,0 +1,53 @@
+/* Copyright 2015, Michele Santullo
+ * This file is part of "Jumping in D".
+ *
+ * "Jumping in D" is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * "Jumping in D" is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with "Jumping in D".  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+module rect;
+import std.traits : isNumeric, isAssignable;
+
+struct Rect(T) {
+	this (in T parLeft, in T parTop, in T parRight, in T parBottom) {
+		m_left = parLeft;
+		m_top = parTop;
+		m_right = parRight;
+		m_bottom = parBottom;
+	}
+
+	@property ref inout(T) left() inout { return m_left; }
+	@property ref inout(T) top() inout { return m_top; }
+	@property ref inout(T) right() inout { return m_right; }
+	@property ref inout(T) bottom() inout { return m_bottom; }
+	static if (isAssignable!T) {
+		@property ref T left(in T parLeft) { return m_left = parLeft; }
+		@property ref T top(in T parTop) { return m_top = parTop; }
+		@property ref T right(in T parRight) { return m_right = parRight; }
+		@property ref T bottom(in T parBottom) { return m_bottom = parBottom; }
+	}
+	static if (isNumeric!T) {
+		@property diff_t width() const { return m_right - m_left; }
+		@property diff_t height() const { return m_bottom - m_top; }
+	}
+
+private:
+	static if (isNumeric!T) {
+		alias diff_t = typeof(m_right - m_left);
+	}
+
+	T m_left;
+	T m_top;
+	T m_right;
+	T m_bottom;
+}

src/vector.d

@@ -34,6 +34,39 @@ struct Vector(T, int N) {
 		fill(m_data[], parInit[0]);
 	}
 
+	//Define mathematical operators
+	//Note the use of auto ref. This is only allowed in function templates, and
+	//instructs the compiler to generate a byref and byvalue version of the same
+	//function. It is necessary to have a byvalue function; if you don't provide
+	//one, the following code: v += Vector!(int, 2)(1, 2);
+	//won't compile as the temporary created on the rhs can't be bound to a
+	//const ref in D.
+	ref Vector!(T,N) opOpAssign(string op)(auto ref const(Vector!(T,N)) parOther) {
+		for (int z = 0; z < N; ++z) {
+			mixin("m_data[z] "~op~"= parOther.m_data[z];");
+		}
+		return this;
+	}
+	ref Vector!(T,N) opOpAssign(string op)(T parOther) {
+		for (int z = 0; z < N; ++z) {
+			mixin("m_data[z] "~op~"= parOther;");
+		}
+		return this;
+	}
+	Vector!(T,N) opBinary(string op)(Vector!(T,N) parOther) {
+		for (int z = 0; z < N; ++z) {
+			mixin("parOther.m_data[z] = m_data[z] "~op~" parOther.m_data[z];");
+		}
+		return parOther;
+	}
+	Vector!(T,N) opBinary(string op)(T parOther) {
+		auto retval = Vector!(T,N)(this);
+		for (int z = 0; z < N; ++z) {
+			mixin("retval "~op~"= parOther;");
+		}
+		return parOther;
+	}
+
 	//Define x, y, z, w accessors. Vectors larger than 4 elements won't have any
 	//of those.
 	static if (N <= 4) {
@@ -111,4 +144,10 @@ unittest {
 	assert(Vector!(int, 2)(3, 0) == v2.x0);
 	assert(Vector!(int, 2)(4, 0) == v2.y0);
 	assert(Vector!(int, 3)(5, 4, 3) == v2.zyx);
+
+	v2 += Vector!(int, 4)(1, 2, 3, 4);
+	assert(4 == v2.x);
+	assert(6 == v2.y);
+	assert(8 == v2.z);
+	assert(10 == v2.w);
 }