# SDL: \[ps2\] fix incorrect blend mode processing

**URL:** <https://discourse.libsdl.org/t/sdl-ps2-fix-incorrect-blend-mode-processing/69429>\
**Category:** SDL Commits\
**Created:** [September 30, 2026, 9:04am UTC](https://discourse.libsdl.org/t/sdl-ps2-fix-incorrect-blend-mode-processing/69429 "2026-09-30T09:04:26Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![SDLPushPostBot](https://discourse.libsdl.org/user_avatar/discourse.libsdl.org/sdlpushpostbot/32/4370_2.png) [@SDLPushPostBot](https://discourse.libsdl.org/u/SDLPushPostBot)\
**Post date:** [September 30, 2026, 9:04am UTC](https://discourse.libsdl.org/t/sdl-ps2-fix-incorrect-blend-mode-processing/69429/1 "2026-09-30T09:04:26Z")

</div>

> <https://github.com/libsdl-org/SDL/commit/a90bcfc73abec32e163dd91a1f09de805298b603>
>
> (cherry picked from commit f4b688bcbd3b498a5c7a1758256aa582b846ab10)

```diff
From a90bcfc73abec32e163dd91a1f09de805298b603 Mon Sep 17 00:00:00 2001
From: onesixromcom <[EMAIL REDACTED]>
Date: Wed, 30 Sep 2026 01:54:53 +0300
Subject: [PATCH] [ps2] fix incorrect blend mode processing

(cherry picked from commit f4b688bcbd3b498a5c7a1758256aa582b846ab10)
---
 src/render/ps2/SDL_render_ps2.c | 30 +++++++++++++++++++-----------
 1 file changed, 19 insertions(+), 11 deletions(-)

diff --git a/src/render/ps2/SDL_render_ps2.c b/src/render/ps2/SDL_render_ps2.c
index 06ad216588945..411d192318e4b 100644
--- a/src/render/ps2/SDL_render_ps2.c
+++ b/src/render/ps2/SDL_render_ps2.c
@@ -108,7 +108,7 @@ static gs_rgbaq float_color_to_RGBAQ(const SDL_FColor *color, float color_scale)
     uint8_t colorR = (uint8_t)SDL_roundf(SDL_clamp(color->r * color_scale, 0.0f, 1.0f) * 255.0f);
     uint8_t colorG = (uint8_t)SDL_roundf(SDL_clamp(color->g * color_scale, 0.0f, 1.0f) * 255.0f);
     uint8_t colorB = (uint8_t)SDL_roundf(SDL_clamp(color->b * color_scale, 0.0f, 1.0f) * 255.0f);
- uint8_t colorA = (uint8_t)SDL_roundf(SDL_clamp(color->a, 0.0f, 1.0f) * 255.0f);
+ uint8_t colorA = (uint8_t)SDL_roundf(SDL_clamp(color->a, 0.0f, 1.0f) * 0x80);
 
     return color_to_RGBAQ(colorR, colorG, colorB, colorA, 0x00);
 }
@@ -118,7 +118,7 @@ static gs_rgbaq float_color_to_RGBAQ_tex(const SDL_FColor *color, float color_sc
     uint8_t colorR = (uint8_t)SDL_roundf(SDL_clamp(color->r * color_scale, 0.0f, 1.0f) * 127.0f);
     uint8_t colorG = (uint8_t)SDL_roundf(SDL_clamp(color->g * color_scale, 0.0f, 1.0f) * 127.0f);
     uint8_t colorB = (uint8_t)SDL_roundf(SDL_clamp(color->b * color_scale, 0.0f, 1.0f) * 127.0f);
- uint8_t colorA = (uint8_t)SDL_roundf(SDL_clamp(color->a, 0.0f, 1.0f) * 127.0f);
+ uint8_t colorA = (uint8_t)SDL_roundf(SDL_clamp(color->a, 0.0f, 1.0f) * 0x80);
 
     return color_to_RGBAQ(colorR, colorG, colorB, colorA, 0x00);
 }
@@ -128,7 +128,7 @@ static uint64_t float_GS_SETREG_RGBAQ(const SDL_FColor *color, float color_scale
     uint8_t colorR = (uint8_t)SDL_roundf(SDL_clamp(color->r * color_scale, 0.0f, 1.0f) * 255.0f);
     uint8_t colorG = (uint8_t)SDL_roundf(SDL_clamp(color->g * color_scale, 0.0f, 1.0f) * 255.0f);
     uint8_t colorB = (uint8_t)SDL_roundf(SDL_clamp(color->b * color_scale, 0.0f, 1.0f) * 255.0f);
- uint8_t colorA = (uint8_t)SDL_roundf(SDL_clamp(color->a, 0.0f, 1.0f) * 255.0f);
+ uint8_t colorA = (uint8_t)SDL_roundf(SDL_clamp(color->a, 0.0f, 1.0f) * 0x80);
 
     return GS_SETREG_RGBAQ(colorR, colorG, colorB, colorA, 0x00);
 }
@@ -190,14 +190,22 @@ static bool PS2_UpdateTexture(SDL_Renderer *renderer, SDL_Texture *texture,
 
     PS2_LockTexture(renderer, texture, rect, (void **)&dst, &dpitch);
     length = rect->w * SDL_BYTESPERPIXEL(texture->format);
- if (length == pitch && length == dpitch) {
- SDL_memcpy(dst, src, length * rect->h);
- } else {
- for (row = 0; row < rect->h; ++row) {
- SDL_memcpy(dst, src, length);
- src += pitch;
- dst += dpitch;
+ const bool has_alpha32 = (SDL_BYTESPERPIXEL(texture->format) == 4 &&
+ SDL_ISPIXELFORMAT_ALPHA(texture->format));
+
+ for (row = 0; row < rect->h; ++row) {
+ SDL_memcpy(dst, src, length);
+
+ // Convert alpha from 0-255 to the GS range 0-0x80
+ if (has_alpha32) {
+ for (int x = 0; x < rect->w; ++x) {
+ Uint8 a = dst[x * 4 + 3];
+ dst[x * 4 + 3] = (Uint8)((a * 128 + 127) / 255);
+ }
         }
+
+ src += pitch;
+ dst += dpitch;
     }
 
     PS2_UnlockTexture(renderer, texture);
@@ -671,7 +679,7 @@ static bool PS2_CreateRenderer(SDL_Renderer *renderer, SDL_Window *window, SDL_P
     } else {
         gsGlobal->Interlace = GS_INTERLACED;
     }
-    
+
     // GS width/height
     gsGlobal->Width = 0;
     gsGlobal->Height = 0;

```