From 18a5e888bbeda989aba6576e7dd7e2b6c09b45ea Mon Sep 17 00:00:00 2001 From: Tony Wasserka Date: Sun, 28 Dec 2014 23:28:58 +0100 Subject: GPU: Pseudo-implement horizontal scaling. It's not really known how this actually works. Some testing has shown that this probably performs no filtering, and common usage in games suggests it's not actually resizing the image at all. However, this patch does seem to fix some homebrew showing quasi-duplicated images while still keeping other applications in a working state. --- src/core/hw/gpu.cpp | 6 +++++- src/core/hw/gpu.h | 3 +++ 2 files changed, 8 insertions(+), 1 deletion(-) diff --git a/src/core/hw/gpu.cpp b/src/core/hw/gpu.cpp index dd619cb16..0ff6c6cde 100644 --- a/src/core/hw/gpu.cpp +++ b/src/core/hw/gpu.cpp @@ -94,11 +94,15 @@ inline void Write(u32 addr, const T data) { int r, g, b, a; } source_color = { 0, 0, 0, 0 }; + // Cheap emulation of horizontal scaling: Just skip each second pixel of the + // input framebuffer. We keep track of this in the pixel_skip variable. + unsigned pixel_skip = (config.scale_horizontally != 0) ? 2 : 1; + switch (config.input_format) { case Regs::PixelFormat::RGBA8: { // TODO: Most likely got the component order messed up. - u8* srcptr = source_pointer + x * 4 + y * config.input_width * 4; + u8* srcptr = source_pointer + x * 4 * pixel_skip + y * config.input_width * 4 * pixel_skip; source_color.r = srcptr[0]; // blue source_color.g = srcptr[1]; // green source_color.b = srcptr[2]; // red diff --git a/src/core/hw/gpu.h b/src/core/hw/gpu.h index 292f496c1..7de055232 100644 --- a/src/core/hw/gpu.h +++ b/src/core/hw/gpu.h @@ -157,6 +157,9 @@ struct Regs { BitField< 8, 3, PixelFormat> input_format; BitField<12, 3, PixelFormat> output_format; BitField<16, 1, u32> output_tiled; // stores output in a tiled format + + // TODO: Not really sure if this actually scales, or even resizes at all. + BitField<24, 1, u32> scale_horizontally; }; INSERT_PADDING_WORDS(0x1); -- cgit v1.2.3