omar/panopainter
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Move readback format mapping to renderer gl

Browse Source
This commit is contained in:
omigamedev
2026-06-02 06:27:29 +02:00
parent 9ce49ef19c
commit 75dfc85978
6 changed files with 117 additions and 13 deletions
Download Patch File Download Diff File Expand all files Collapse all files

3
docs/modernization/build-inventory.md
View File

@@ -129,7 +129,8 @@ Known local toolchain state:
GLES float/half-float extensions, WebGL exclusion behavior, and the
upload-type mapping used by legacy `Texture2D` and `RTT` creation. It also
validates image channel-count to OpenGL texture format mapping, including
invalid channel counts rejected by `Texture2D::create(Image)`, and
invalid channel counts rejected by `Texture2D::create(Image)`, RGBA8/RGBA32F
readback formats and byte-count math used by `RTT` and `PBO` readbacks, and
framebuffer status naming used by `RTT` diagnostics. It also owns and
validates framebuffer blit color mask and linear/nearest filters used by
`RTT::resize` and `RTT::copy`, plus the default linear clamp-to-edge

13
docs/modernization/roadmap.md
View File

@@ -390,9 +390,11 @@ OpenGL capability detection for framebuffer fetch, map-buffer alignment, and
float texture support. It also owns the OpenGL texture upload-type mapping used
by legacy `Texture2D` and `RTT` creation, plus image channel-count to texture
format mapping for `Texture2D` image uploads and framebuffer status naming for
`RTT` diagnostics. The framebuffer blit color mask and linear/nearest filter
tokens used by `RTT::resize` and `RTT::copy`, plus the default render-target
texture parameters used by `RTT::create`, also live in `pp_renderer_gl`.
`RTT` diagnostics. RGBA8/RGBA32F readback formats and byte-count math used by
`RTT` and `PBO` readbacks now live in `pp_renderer_gl`. The framebuffer blit
color mask and linear/nearest filter tokens used by `RTT::resize` and
`RTT::copy`, plus the default render-target texture parameters used by
`RTT::create`, also live in `pp_renderer_gl`.
Mesh index-type and primitive-mode
decisions used by legacy `Shape` drawing and the PanoPainter cube-face to
OpenGL texture-target mapping used by `TextureCube` also live in
@@ -646,8 +648,9 @@ Results:
alignment, desktop GL core float support, GLES float/half-float extensions,
WebGL exclusion behavior, upload types for RGBA8/RGBA16F/RGBA32F internal
formats, image channel-count format mapping including invalid counts, and
framebuffer status names, framebuffer blit color mask and linear/nearest
filters, plus Shape index-type and fill/stroke primitive mode mapping,
RGBA8/RGBA32F readback format and byte-count mapping, framebuffer status
names, framebuffer blit color mask and linear/nearest filters, plus Shape
index-type and fill/stroke primitive mode mapping,
PanoPainter cube-face texture-target order, and the linear clamp-to-edge
render-target texture parameter set used by `RTT::create`.
Sampler parameter validation covers wrap S/T/R plus min/mag filter ordering

26
src/renderer_gl/opengl_capabilities.cpp
View File

@@ -123,6 +123,32 @@ OpenGlPixelFormat texture_format_for_channel_count(std::uint32_t channel_count)
}
}
OpenGlReadbackFormat rgba8_readback_format() noexcept
{
return OpenGlReadbackFormat {
.pixel_format = gl_rgba,
.component_type = gl_unsigned_byte,
.bytes_per_pixel = 4U,
};
}
OpenGlReadbackFormat rgba32f_readback_format() noexcept
{
return OpenGlReadbackFormat {
.pixel_format = gl_rgba,
.component_type = gl_float,
.bytes_per_pixel = 16U,
};
}
std::uint64_t readback_byte_count(
OpenGlReadbackFormat format,
std::uint32_t width,
std::uint32_t height) noexcept
{
return static_cast<std::uint64_t>(width) * height * format.bytes_per_pixel;
}
const char* framebuffer_status_name(std::uint32_t status) noexcept
{
switch (status) {

12
src/renderer_gl/opengl_capabilities.h
View File

@@ -32,12 +32,24 @@ struct OpenGlTextureParameter {
std::uint32_t value = 0;
};
struct OpenGlReadbackFormat {
std::uint32_t pixel_format = 0;
std::uint32_t component_type = 0;
std::uint32_t bytes_per_pixel = 0;
};
[[nodiscard]] OpenGlCapabilities detect_opengl_capabilities(
std::span<const std::string_view> extensions,
OpenGlRuntime runtime) noexcept;
[[nodiscard]] std::uint32_t texture_upload_type_for_internal_format(std::uint32_t internal_format) noexcept;
[[nodiscard]] OpenGlPixelFormat texture_format_for_channel_count(std::uint32_t channel_count) noexcept;
[[nodiscard]] OpenGlReadbackFormat rgba8_readback_format() noexcept;
[[nodiscard]] OpenGlReadbackFormat rgba32f_readback_format() noexcept;
[[nodiscard]] std::uint64_t readback_byte_count(
OpenGlReadbackFormat format,
std::uint32_t width,
std::uint32_t height) noexcept;
[[nodiscard]] const char* framebuffer_status_name(std::uint32_t status) noexcept;
[[nodiscard]] std::uint32_t framebuffer_color_buffer_mask() noexcept;
[[nodiscard]] std::uint32_t framebuffer_blit_filter(bool linear) noexcept;

59
src/rtt.cpp
View File

@@ -358,10 +358,18 @@ uint8_t* RTT::readTextureData(uint8_t* buffer) const noexcept
buffer = createBuffer();
App::I->render_task([&]
{
const auto readback = pp::renderer::gl::rgba8_readback_format();
GLint old;
glGetIntegerv(GL_READ_FRAMEBUFFER_BINDING, &old);
glBindFramebuffer(GL_READ_FRAMEBUFFER, fboID);
glReadPixels(0, 0, w, h, GL_RGBA, GL_UNSIGNED_BYTE, buffer);
glReadPixels(
0,
0,
w,
h,
static_cast<GLenum>(readback.pixel_format),
static_cast<GLenum>(readback.component_type),
buffer);
glBindFramebuffer(GL_READ_FRAMEBUFFER, old);
});
return buffer;
@@ -375,10 +383,18 @@ float* RTT::readTextureDataFloat(float* buffer) const noexcept
buffer = createBufferFloat();
App::I->render_task([&]
{
const auto readback = pp::renderer::gl::rgba32f_readback_format();
GLint old;
glGetIntegerv(GL_READ_FRAMEBUFFER_BINDING, &old);
glBindFramebuffer(GL_READ_FRAMEBUFFER, fboID);
glReadPixels(0, 0, w, h, GL_RGBA, GL_FLOAT, buffer);
glReadPixels(
0,
0,
w,
h,
static_cast<GLenum>(readback.pixel_format),
static_cast<GLenum>(readback.component_type),
buffer);
glBindFramebuffer(GL_READ_FRAMEBUFFER, old);
});
return buffer;
@@ -386,12 +402,21 @@ float* RTT::readTextureDataFloat(float* buffer) const noexcept
uint8_t* RTT::createBuffer() const noexcept
{
return new uint8_t[w * h * 4];
const auto readback = pp::renderer::gl::rgba8_readback_format();
return new uint8_t[pp::renderer::gl::readback_byte_count(
readback,
static_cast<std::uint32_t>(w),
static_cast<std::uint32_t>(h))];
}
float * RTT::createBufferFloat() const noexcept
{
return new float[w * h * 4];
const auto readback = pp::renderer::gl::rgba32f_readback_format();
return new float[pp::renderer::gl::readback_byte_count(
readback,
static_cast<std::uint32_t>(w),
static_cast<std::uint32_t>(h))
/ sizeof(float)];
}
void RTT::bindTexture()
@@ -467,11 +492,26 @@ bool PBO::create(RTT& rtt) noexcept
App::I->render_task([this, &rtt] {
width = rtt.getWidth();
height = rtt.getHeight();
const auto readback = pp::renderer::gl::rgba8_readback_format();
rtt.bindFramebuffer();
glGenBuffers(1, &buffer_id);
glBindBuffer(GL_PIXEL_PACK_BUFFER, buffer_id);
glBufferData(GL_PIXEL_PACK_BUFFER, width * height * 4, 0, GL_STREAM_READ);
glReadPixels(0, 0, width, height, GL_RGBA, GL_UNSIGNED_BYTE, 0);
glBufferData(
GL_PIXEL_PACK_BUFFER,
static_cast<GLsizeiptr>(pp::renderer::gl::readback_byte_count(
readback,
static_cast<std::uint32_t>(width),
static_cast<std::uint32_t>(height))),
0,
GL_STREAM_READ);
glReadPixels(
0,
0,
width,
height,
static_cast<GLenum>(readback.pixel_format),
static_cast<GLenum>(readback.component_type),
0);
glBindBuffer(GL_PIXEL_PACK_BUFFER, 0);
rtt.unbindFramebuffer();
});
@@ -513,9 +553,14 @@ void PBO::unbind() noexcept
glm::uint8_t* PBO::map() noexcept
{
App::I->render_task([this] {
const auto readback = pp::renderer::gl::rgba8_readback_format();
glBindBuffer(GL_PIXEL_PACK_BUFFER, buffer_id);
mapped_ptr = (GLubyte*)glMapBufferRange(GL_PIXEL_PACK_BUFFER, 0,
width * height * 4, GL_MAP_READ_BIT);
static_cast<GLsizeiptr>(pp::renderer::gl::readback_byte_count(
readback,
static_cast<std::uint32_t>(width),
static_cast<std::uint32_t>(height))),
GL_MAP_READ_BIT);
glBindBuffer(GL_PIXEL_PACK_BUFFER, 0);
});
return mapped_ptr;

17
tests/renderer_gl/capabilities_tests.cpp
View File

@@ -116,6 +116,22 @@ void maps_image_channel_count_to_texture_format(pp::tests::Harness& h)
PP_EXPECT(h, invalid.pixel_format == 0U);
}
void maps_readback_formats(pp::tests::Harness& h)
{
const auto rgba8 = pp::renderer::gl::rgba8_readback_format();
const auto rgba32f = pp::renderer::gl::rgba32f_readback_format();
PP_EXPECT(h, rgba8.pixel_format == 0x1908U);
PP_EXPECT(h, rgba8.component_type == 0x1401U);
PP_EXPECT(h, rgba8.bytes_per_pixel == 4U);
PP_EXPECT(h, pp::renderer::gl::readback_byte_count(rgba8, 3U, 5U) == 60U);
PP_EXPECT(h, rgba32f.pixel_format == 0x1908U);
PP_EXPECT(h, rgba32f.component_type == 0x1406U);
PP_EXPECT(h, rgba32f.bytes_per_pixel == 16U);
PP_EXPECT(h, pp::renderer::gl::readback_byte_count(rgba32f, 3U, 5U) == 240U);
}
void names_framebuffer_status_codes(pp::tests::Harness& h)
{
PP_EXPECT(h, pp::renderer::gl::framebuffer_status_name(0x8CD5U) == std::string_view("GL_FRAMEBUFFER_COMPLETE"));
@@ -322,6 +338,7 @@ int main()
harness.run("ignores_gles_texture_extensions_for_webgl_runtime", ignores_gles_texture_extensions_for_webgl_runtime);
harness.run("selects_texture_upload_type_from_internal_format", selects_texture_upload_type_from_internal_format);
harness.run("maps_image_channel_count_to_texture_format", maps_image_channel_count_to_texture_format);
harness.run("maps_readback_formats", maps_readback_formats);
harness.run("names_framebuffer_status_codes", names_framebuffer_status_codes);
harness.run("maps_framebuffer_blit_parameters", maps_framebuffer_blit_parameters);
harness.run("maps_shape_index_and_primitive_modes", maps_shape_index_and_primitive_modes);