From e27c322003a77f8cfa3ff52206d01ffdcd6fc3cf Mon Sep 17 00:00:00 2001
From: Nathan Misner <nathan@infochunk.com>
Date: Sun, 5 Jun 2022 15:55:33 -0400
Subject: [PATCH] added alpha transparency for blocks

---
 block.cpp | 30 +++++++++++++++++++++++++++---
 block.h   |  7 ++++---
 level.cpp |  3 +++
 level.h   |  3 +++
 4 files changed, 37 insertions(+), 6 deletions(-)

diff --git a/block.cpp b/block.cpp
index 7920cba..51fc75e 100644
--- a/block.cpp
+++ b/block.cpp
@@ -28,14 +28,27 @@ static std::vector<std::unique_ptr<PakFrame>> blockTextures;
 static std::vector<std::unique_ptr<PakFrame>> tutorialBlockTextures;
 static SDL_Rect blockRect;
 
-Block::Block(float xPos, float yPos, int type, int mode, Level *parent) {
+Block::Block(float xPos, float yPos, int type, int mode, Level *parent) :
+    SpriteInfo(NULL, NULL, &blockRect)
+{
     x = xPos;
     y = yPos;
+    alpha = 255;
     this->type = type;
     this->mode = mode;
     this->parent = parent;
     crack = BlockCrack();
     shine = BlockShine();
+
+    // initialize textures
+    if (type != INV) {
+        if (mode == BLOCK_MODE_NORMAL) {
+            texture = blockTextures[type]->texture;
+        }
+        else if (mode == BLOCK_MODE_TUTORIAL) {
+            texture = tutorialBlockTextures[type]->texture;
+        }
+    }
 }
 
 int Block::shouldBounce(int power) {
@@ -147,7 +160,19 @@ int Block::collide(int power) {
     }
 }
 
+void Block::setAlpha(int alpha) {
+    // small optimization so i can call this function every frame in level.cpp
+    if (alpha != this->alpha) {
+        SpriteInfo::setAlpha(alpha);
+    }
+}
+
 void Block::draw() {
+    if (type != INV) {
+        if (mode == BLOCK_MODE_NORMAL) {
+            texture = blockTextures[type]->texture;
+        }
+    }
     if (type == INV) {
         // don't draw invisible blocks
         return;
@@ -162,12 +187,11 @@ void Block::draw() {
     }
     spr.x = x;
     spr.y = y;
+    spr.setAlpha(alpha);
     spr.draw();
 }
 
 void Block_Init() {
-    printf("---block_init---\n");
-
     blockTextures = Sprite_LoadPak("block.pak");
     tutorialBlockTextures = Sprite_LoadPak("tutorialblock.pak");
     blockRect.x = 0;
diff --git a/block.h b/block.h
index e488943..7a2b8d7 100644
--- a/block.h
+++ b/block.h
@@ -64,10 +64,9 @@ class Level;
 #define BLOCK_WIDTH (16)
 #define BLOCK_HEIGHT (8)
 
-class Block {
+class Block : public SpriteInfo{
 public:
-    float x;
-    float y;
+    int alpha;
     int type;
     int mode;
     Level *parent;
@@ -80,6 +79,8 @@ public:
     Block(float xPos, float yPos, int type, int mode, Level *parent);
     int shouldBounce(int power);
     int collide(int power);
+    // makes the block partially transparent. alpha should be between 0 and 255
+    void setAlpha(int alpha);
     void draw();
 };
 
diff --git a/level.cpp b/level.cpp
index 16e13bc..3347179 100644
--- a/level.cpp
+++ b/level.cpp
@@ -98,6 +98,7 @@ Level::Level(int xPos, int yPos, int num, int mode) {
     Block_Stretch_RemoveAll();
 
     levelNum = num;
+    alpha = 255; // level should start opaque
 
     this->mode = mode;
     if (mode == BLOCK_MODE_TUTORIAL) {
@@ -195,6 +196,7 @@ void Level::animate() {
     else {
         for (Block &block : animRow) {
             block.y = rowY;
+            block.setAlpha(alpha);
             block.draw();
         }
     }
@@ -247,6 +249,7 @@ void Level::disp() {
 
     //draw all the blocks in the block arr
     for (Block &block : blocks) {
+        block.setAlpha(alpha);
         block.draw();
         block.shine.move(block.x, block.y);
         block.shine.draw();
diff --git a/level.h b/level.h
index 03d4832..673303d 100644
--- a/level.h
+++ b/level.h
@@ -49,6 +49,9 @@ private:
 	// where the level is on the screen
 	int xPos;
 	int yPos;
+	// transparency on the level, should be between 0 and 255. Used for fade-outs
+	// at the end of a stage
+	int alpha;
 	// how fast the blocks move during animations
 	float blockSpeed;
 	// mover blocks
-- 
2.45.2