CLOSES #1231, CLOSES #1269, CLOSES #1301

tests/engine/gen2_shadow_ball_bgp_view_bug1269.lua

@@ -0,0 +1,86 @@
+-- engine/battle_anims/anim_commands.asm:1293 BattleAnim_SetBGPals
+--
+-- gen2_shadow_ball_bgp_bug1269.lua proves the runner lands bg.bgp and that
+-- panelPalettes/remapTable would invert correctly; it never calls
+-- BattleAnimView:present, which is where #1269 actually lived (the byte
+-- was landed but nothing read it). This suite drives present() itself and
+-- watches the shader binding around the backdrop draw.
+
+package.path = "./?.lua;./?/init.lua;" .. package.path
+
+love = require("tests.love_stub")
+
+-- A remap shader that never touches the GPU: present() only needs
+-- love.graphics.newShader to succeed so GbcPalette.remapShader() is
+-- non-nil, which is the gate `present` checks before it will bake+remap.
+local sentShader = { calls = {} }
+function sentShader:send(name, ...) self.calls[#self.calls + 1] = name end
+love.graphics.newShader = function() return sentShader end
+
+-- The stub's stand-in Quad has no setViewport/getViewport, which blitRow
+-- (the scanline blit present() drives 144 times a frame) needs; the real
+-- love.graphics.Quad has both.
+love.graphics.newQuad = function(x, y, w, h)
+  local q = { x = x, y = y, w = w, h = h }
+  function q:setViewport(x2, y2, w2, h2) self.x, self.y, self.w, self.h = x2, y2, w2, h2 end
+  function q:getViewport() return self.x, self.y, self.w, self.h end
+  return q
+end
+
+local T = require("tests.harness")
+local GbcPalette = require("src.render.GbcPalette")
+local BattleAnimView = require("src.ui.gen2.BattleAnimView")
+
+local shaderDuringFill = "unset"
+local realRectangle = love.graphics.rectangle
+love.graphics.rectangle = function(...)
+  if shaderDuringFill == "unset" then
+    shaderDuringFill = love.graphics.getShader()
+  end
+  return realRectangle(...)
+end
+
+local view = BattleAnimView.new({}, nil)
+-- data/moves/animations.asm:4509 BattleAnim_ShadowBall's anim_bgp $1b, with
+-- no scroll and no rBGP window queued, is exactly the frame that used to
+-- fall through the old `needsCanvas`-only early-out untouched.
+local runner = {
+  bg = {
+    bgp = 0x1b,
+    lcdc = nil,
+    scx = 0,
+    scy = 0,
+    lyStart = 0,
+    lyEnd = 0,
+    lyBackup = {},
+  },
+}
+
+T.check(love.graphics.getShader() == nil, "no shader bound before present")
+
+view:present(runner, function() end, nil)
+
+T.check(shaderDuringFill == sentShader,
+  "the panel backdrop is drawn through the remap shader, not plainly")
+T.check(love.graphics.getShader() == nil,
+  "the shader is unbound again once present returns, so drawObjects is unaffected")
+
+local sawRemapSend = false
+for _, name in ipairs(sentShader.calls) do
+  if name == "remapSrc" then sawRemapSend = true end
+end
+T.check(sawRemapSend, "GbcPalette.useRemap actually sent a remap table, not just bound the shader")
+
+-- The identity byte must take the plain path: no bake, no shader, ever.
+shaderDuringFill = "unset"
+local identityRunner = {
+  bg = { bgp = GbcPalette.BGP_IDENTITY, lcdc = nil, scx = 0, scy = 0,
+    lyStart = 0, lyEnd = 0, lyBackup = {} },
+}
+local plainDrawCalled = false
+view:present(identityRunner, function() plainDrawCalled = true end, nil)
+T.check(plainDrawCalled, "identity rBGP takes the plain drawBg() path")
+T.check(shaderDuringFill == "unset",
+  "identity rBGP never touches the remap shader")
+
+T.finish("gen2 shadow ball bgp view bug 1269")