From 2d7262aa221bd05bbf19721be984426ac57aa896 Mon Sep 17 00:00:00 2001
From: Doyle Thai <dyl.thai@gmail.com>
Date: Wed, 10 Aug 2016 01:43:26 +1000
Subject: [PATCH] Add basic scrollbar imgui code

---
 src/WorldTraveller.c                 | 89 ++++++++++++++++++++++++++++
 src/include/Dengine/Platform.h       |  1 +
 src/include/Dengine/WorldTraveller.h |  6 ++
 3 files changed, 96 insertions(+)

diff --git a/src/WorldTraveller.c b/src/WorldTraveller.c
index c288f5c..e503fd6 100644
--- a/src/WorldTraveller.c
+++ b/src/WorldTraveller.c
@@ -885,8 +885,24 @@ INTERNAL i32 button(UiState *uiState, AssetManager *assetManager,
 	}
 
 	RenderTex renderTex = renderer_createNullRenderTex(assetManager);
+
+	/* If no widget has keyboard focus, take it */
+	if (uiState->kbdItem == 0)
+		uiState->kbdItem = id;
+
+	/* If we have keyboard focus, show it */
+	if (uiState->kbdItem == id)
+	{
+		// Draw outline
+		renderer_staticRect(renderer, v2_add(V2(-6, -6), rect.pos),
+		                    v2_add(V2(20, 20), rect.size), V2(0, 0), 0, renderTex,
+		                    V4(1.0f, 0, 0, 1));
+	}
+
+	// Draw shadow
 	renderer_staticRect(renderer, v2_add(V2(8, 8), rect.pos), rect.size,
 	                    V2(0, 0), 0, renderTex, V4(0, 0, 0, 1));
+
 	if (uiState->hotItem == id)
 	{
 		if (uiState->activeItem == id)
@@ -906,6 +922,24 @@ INTERNAL i32 button(UiState *uiState, AssetManager *assetManager,
 		                    V2(0, 0), 0, renderTex, V4(0.5f, 0.5f, 0.5f, 1));
 	}
 
+	// After renderering before click check, see if we need to process keys
+	if (uiState->kbdItem == id)
+	{
+		if (input.space)
+		{
+			// Set focus to nothing and let next widget get focus
+			uiState->kbdItem = 0;
+			if (input->leftShift)
+				uiState->kbdItem = uiState->lastWidget;
+
+			// Clear key state so next widget doesn't auto grab
+			input->space     = FALSE;
+			input->leftShift = FALSE;
+		}
+	}
+
+	uiState->lastWidget = id;
+
 	if (!input.mouseLeft &&
 	    uiState->hotItem == id &&
 	    uiState->activeItem == id)
@@ -916,6 +950,56 @@ INTERNAL i32 button(UiState *uiState, AssetManager *assetManager,
 	return 0;
 }
 
+INTERNAL i32 scrollBar(UiState *uiState, AssetManager *assetManager,
+                       Renderer *renderer, KeyInput input, i32 id, Rect rect,
+                       i32 *value, i32 max)
+{
+	i32 yPos = ((256 - 16) * (*value)) / max;
+
+	Rect scrollRect;
+	scrollRect.pos = v2_add(rect.pos, V2i(8, 8));
+	scrollRect.size = V2(16, 255);
+	if (math_pointInRect(scrollRect, input.mouseP))
+	{
+		uiState->hotItem = id;
+		if (uiState->activeItem == 0 && input.mouseLeft)
+			uiState->activeItem = id;
+	}
+
+	v2 scrollBarSize    = V2(32, 256 + 16);
+	RenderTex renderTex = renderer_createNullRenderTex(assetManager);
+	renderer_staticRect(renderer, rect.pos, scrollBarSize, V2(0, 0), 0,
+	                    renderTex, V4(0.5f, 0.5f, 0.5f, 1));
+
+	if (uiState->hotItem == id || uiState->activeItem == id)
+	{
+		renderer_staticRect(renderer, v2_add(V2i(8, 8 + yPos), rect.pos),
+		                    V2(16, 16), V2(0, 0), 0, renderTex,
+		                    V4(1.0f, 0, 0, 1));
+	}
+	else
+	{
+		renderer_staticRect(renderer, v2_add(V2i(8, 8 + yPos), rect.pos),
+		                    V2(16, 16), V2(0, 0), 0, renderTex,
+		                    V4(0, 1.0f, 0, 1));
+	}
+
+	if (uiState->activeItem == id)
+	{
+		i32 mousePos = CAST(i32)(input.mouseP.y - (rect.pos.y + 8));
+		if (mousePos < 0) mousePos = 0;
+		if (mousePos > 255) mousePos = 255;
+		i32 v = (mousePos * max) / 255;
+		if (v != *value)
+		{
+			*value = v;
+			return 1;
+		}
+	}
+
+	return 0;
+}
+
 void worldTraveller_gameUpdateAndRender(GameState *state, f32 dt)
 {
 	if (dt >= 1.0f) dt = 1.0f;
@@ -1178,6 +1262,11 @@ void worldTraveller_gameUpdateAndRender(GameState *state, f32 dt)
 	button(&state->uiState, assetManager, renderer, state->input, 3,
 	       buttonRectC);
 
+	LOCAL_PERSIST i32 scrollValue = 30;
+	Rect scrollRectA = {V2(900, 500), V2(16, 255)};
+	scrollBar(&state->uiState, assetManager, renderer, state->input, 3,
+	          scrollRectA, &scrollValue, 160);
+
 	// RESET IMGUI
 	if (!state->input.mouseLeft)             state->uiState.activeItem = 0;
 	else if (state->uiState.activeItem == 0) state->uiState.activeItem = -1;
diff --git a/src/include/Dengine/Platform.h b/src/include/Dengine/Platform.h
index ffb20c1..731ac9f 100644
--- a/src/include/Dengine/Platform.h
+++ b/src/include/Dengine/Platform.h
@@ -14,6 +14,7 @@ enum KeyCodes
 	keycode_left,
 	keycode_right,
 	keycode_space,
+	keycode_leftShift,
 	keycode_mouseLeft,
 	keycode_count,
 };
diff --git a/src/include/Dengine/WorldTraveller.h b/src/include/Dengine/WorldTraveller.h
index 56d3e3c..6cbac7b 100644
--- a/src/include/Dengine/WorldTraveller.h
+++ b/src/include/Dengine/WorldTraveller.h
@@ -17,6 +17,12 @@ typedef struct UiState
 {
 	i32 hotItem;
 	i32 activeItem;
+
+	i32 kbdItem;
+	i32 keyEntered;
+	i32 keyMod;
+
+	i32 lastWidget;
 } UiState;
 
 typedef struct World