add simple SDL input handling and callbacks

README

@@ -13,6 +13,7 @@ TODO:
 	add input abstraction for SDL
 	store meshes separately from entities for reuse
 	add a function to update camera transforms only once per frame, per shader
+	fix example Makefile dependenies
 
 Dependencies:
 	assimp >= 5.0.0

examples/assimp_loading/main.cpp

@@ -4,6 +4,7 @@
 
 #include "camera.h"
 #include "dumbLog.h"
+#include "input.h"
 #include "entity.h"
 #include "renderer.h"
 #include "shader_program.h"
@@ -12,11 +13,26 @@
 void
 doFrameCallback(render_state* rs)
 {
+	static input_state is = {};
+	inputProcessEvents(&is);
+
+	if (is.window_closed || is.escape) {
+		rs->running = false;
+		return;
+	}
+
+	int rotate_mod = 0;
+
+	if (is.left)
+		rotate_mod = -1;
+	if (is.right)
+		rotate_mod = 1;
+
 	// NOTE: rotate mesh on z-axis every frame
 	entity& e = rs->render_groups[0].entities[0];
 	static float angle = (float) M_PI_2 / 33;
 	static glm::vec3 axis(0, 0, 1);
-	entRotate(e, angle, axis);
+	entRotate(e, angle * rotate_mod, axis);
 }
 
 // TODO: remove/refactor this when we get animation working

examples/simple_mesh/main.cpp

@@ -2,18 +2,34 @@
 #include <glm/glm.hpp>
 
 #include "dumbLog.h"
+#include "input.h"
 #include "mesh.h"
 #include "renderer.h"
 
 
 void
-doFrameCallback(render_state* rs)
+doFrameCallbackPre(render_state* rs)
 {
+	static input_state is = {};
+	inputProcessEvents(&is);
+
+	if (is.window_closed || is.escape) {
+		rs->running = false;
+		return;
+	}
+
+	int rotate_mod = 0;
+
+	if (is.left)
+		rotate_mod = -1;
+	if (is.right)
+		rotate_mod = 1;
+
 	// NOTE: rotate mesh on z-axis every frame
 	entity& e = rs->render_groups[0].entities[0];
 	static float angle = (float) M_PI_2 / 33;
 	static glm::vec3 axis(0, 0, 1);
-	entRotate(e, angle, axis);
+	entRotate(e, angle * rotate_mod, axis);
 }
 
 simple_mesh*
@@ -65,7 +81,7 @@ main()
 		glm::vec3(0,0,1)
 	);
 
-	renDoRenderLoop(rs, 60, doFrameCallback);
+	renDoRenderLoop(rs, 60, doFrameCallbackPre);
 
 	renShutdown(rs);
 	return 0;

include/input.h

@@ -0,0 +1,16 @@
+
+#pragma once
+
+struct input_state
+{
+	bool window_closed;
+	bool escape;
+	bool left;
+	bool right;
+	bool up;
+	bool down;
+};
+
+void
+inputProcessEvents(input_state* is);
+

include/renderer.h

@@ -47,6 +47,7 @@ struct render_state
 	camera cam;
 	util_RGBA clear_col;
 	SDL_Handles* handles;
+	bool running;
 
 	// TODO: this really needs to be a resizable array, or linked list, or
 	// 	...gasp, std::vector
@@ -70,11 +71,18 @@ void renShutdown(render_state* rs);
 render_group*
 renAllocateGroup(uint entity_count, shader_wrapper shader);
 
+// NOTE: callback function signature to use with renDoRenderLoop()
 typedef void (*frame_callback_fn) (render_state*);
 
-void renDoRenderLoop(render_state* rs,
+// NOTE: There are 2 callbacks to use here, cb_func_pre is called before
+// 	the call to renRenderFrame(), cb_fun_post is called after
+// NOTE: if you use cb_func_pre, you will have to use SDL_PollEvent() manually
+// 	and at minimum set rs->running = false on SDL_QUIT event
+void
+renDoRenderLoop(render_state* rs,
 	uint framerate = 60,
-	frame_callback_fn cb_func = nullptr);
+	frame_callback_fn cb_func_pre = nullptr,
+	frame_callback_fn cb_func_post = nullptr);
 
 void renRenderFrame(render_state* rs);
 

src/input.cpp

@@ -0,0 +1,39 @@
+
+#include <SDL2/SDL.h>
+
+#include "input.h"
+
+
+void
+inputProcessEvents(input_state* is)
+{
+	SDL_Event e;
+
+	while (SDL_PollEvent(&e)) {
+		switch (e.type) {
+			case SDL_QUIT:
+				is->window_closed = true;
+				break;
+			case SDL_KEYDOWN:
+				switch (e.key.keysym.sym) {
+					case SDLK_ESCAPE: is->escape = true; break;
+					case SDLK_LEFT: is->left = true; break;
+					case SDLK_RIGHT: is->right = true; break;
+					case SDLK_UP: is->up = true; break;
+					case SDLK_DOWN: is->down = true; break;
+				}
+				break;
+			case SDL_KEYUP:
+				switch (e.key.keysym.sym) {
+					case SDLK_ESCAPE: is->escape = false; break;
+					case SDLK_LEFT: is->left = false; break;
+					case SDLK_RIGHT: is->right = false; break;
+					case SDLK_UP: is->up = false; break;
+					case SDLK_DOWN: is->down = false; break;
+				}
+				break;
+			default: break;
+		}
+	}
+}
+

src/renderer.cpp

@@ -8,10 +8,11 @@
 #include <glm/geometric.hpp>
 #include <glm/gtc/matrix_transform.hpp>
 
+#include "default_shaders.cpp"
 #include "dumbLog.h"
+#include "input.h"
 #include "render_object.h"
 #include "renderer.h"
-#include "default_shaders.cpp"
 
 #define CLEAR_COL_R 55.f / 255.f
 #define CLEAR_COL_G 55.f / 255.f
@@ -94,27 +95,33 @@ renAllocateGroup(uint entity_count, shader_wrapper shader)
 	return rg;
 }
 
-// TODO: add a better structure for input
 void
-renDoRenderLoop(render_state* rs, uint framerate, frame_callback_fn cb_func)
+renDoRenderLoop(render_state* rs,
+	uint framerate,
+	frame_callback_fn cb_func_pre,
+	frame_callback_fn cb_func_post)
 {
 	uint delay = (framerate > 0) ? 1 / framerate : 0;
 	uint frameStart, frameTime;
-	bool running = true;
+	static input_state is = {};
-	SDL_Event e;
 
-	while (running) {
+	while (rs->running) {
 		frameStart = SDL_GetTicks();
 
-		while (SDL_PollEvent(&e)) {
+		if (cb_func_pre != nullptr) {
-			if ((e.type == SDL_KEYDOWN && e.key.keysym.sym == SDLK_ESCAPE)
+			cb_func_pre(rs);
-				|| e.type == SDL_QUIT) {
+		} else {
-				running = false;
+			inputProcessEvents(&is);
+
+			if (is.window_closed || is.escape) {
+				rs->running = false;
+				return;
 			}
 		}
 
-		if (cb_func != nullptr) cb_func(rs);
 		renRenderFrame(rs);
+		if (cb_func_post != nullptr) cb_func_post(rs);
+
 		SDL_GL_SwapWindow(rs->handles->window);
 		frameTime = SDL_GetTicks() - frameStart;
 
@@ -287,6 +294,7 @@ openglDebugCallback(GLenum source, GLenum type, GLuint id, GLenum severity,
 void
 setDefaults(render_state* rs, glm::vec2 viewport_dims)
 {
+	rs->running = true;
 	rs->viewport_dims = viewport_dims;
 	rs->lights = lightsInit();
 	rs->clear_col.R = CLEAR_COL_R;