diff options
author | Benjamin Barenblat <bbarenblat@gmail.com> | 2022-01-17 23:12:32 -0500 |
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committer | Benjamin Barenblat <bbarenblat@gmail.com> | 2022-01-30 15:55:27 -0500 |
commit | d0e18bdb7924c71cdca8dd983711171d87ef28be (patch) | |
tree | 6be11aae0b7c8874e6507b75b4ef26d1353952c7 /src/gl/buffer.cc |
glplanet draws Earth like it currently appears from space, putting
nighttime areas in shadow and daytime areas in light. It’s modeled
after Xplanet (http://xplanet.sourceforge.net/), but whereas Xplanet is
entirely a CPU-resident program, glplanet draws using OpenGL. It’s thus
much less resource-intensive, particularly when using high-resolution
textures.
Diffstat (limited to 'src/gl/buffer.cc')
-rw-r--r-- | src/gl/buffer.cc | 105 |
1 files changed, 105 insertions, 0 deletions
diff --git a/src/gl/buffer.cc b/src/gl/buffer.cc new file mode 100644 index 0000000..a56e36a --- /dev/null +++ b/src/gl/buffer.cc @@ -0,0 +1,105 @@ +// Copyright 2021 Benjamin Barenblat +// +// Licensed under the Apache License, Version 2.0 (the "License"); you may not +// use this file except in compliance with the License. You may obtain a copy of +// the License at +// +// https://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT +// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the +// License for the specific language governing permissions and limitations under +// the License. + +#include "src/gl/buffer.h" + +#include <stdint.h> + +#include <stdexcept> + +#include "src/gl/error.h" +#include "src/util.h" +#include "third_party/abseil/absl/strings/substitute.h" +#include "third_party/glew/include/GL/glew.h" + +namespace gl { + +namespace { + +constexpr uint16_t Pack(Buffer::AccessFrequency frequency, + Buffer::AccessNature nature) noexcept { + static_assert(sizeof(Buffer::AccessFrequency) == 1); + static_assert(sizeof(Buffer::AccessNature) == 1); + return FromEnum(frequency) << 8 | FromEnum(nature); +} + +GLenum CombineFrequencyAndNature(Buffer::AccessFrequency frequency, + Buffer::AccessNature nature) { + using F = ::gl::Buffer::AccessFrequency; + using N = ::gl::Buffer::AccessNature; + switch (Pack(frequency, nature)) { + case Pack(F::kStream, N::kDraw): + return GL_STREAM_DRAW; + case Pack(F::kStream, N::kRead): + return GL_STREAM_READ; + case Pack(F::kStream, N::kCopy): + return GL_STREAM_COPY; + + case Pack(F::kStatic, N::kDraw): + return GL_STATIC_DRAW; + case Pack(F::kStatic, N::kRead): + return GL_STATIC_READ; + case Pack(F::kStatic, N::kCopy): + return GL_STATIC_COPY; + + case Pack(F::kDynamic, N::kDraw): + return GL_DYNAMIC_DRAW; + case Pack(F::kDynamic, N::kRead): + return GL_DYNAMIC_READ; + case Pack(F::kDynamic, N::kCopy): + return GL_DYNAMIC_COPY; + + default: + throw std::invalid_argument(absl::Substitute( + "GL: invalid access frequency and/or nature ($0, $1)", + FromEnum(frequency), FromEnum(nature))); + } +} + +} // namespace + +Buffer::Buffer(const Buffer& other) + : size_bytes_(other.size_bytes_), + frequency_(other.frequency_), + nature_(other.nature_) { + gl_internal::CheckThreadSafety(); + + glCreateBuffers(1, &buffer_); + gl_internal::UnnecessaryErrorCheck(); + + glNamedBufferData(buffer_, size_bytes_, /*data=*/nullptr, + CombineFrequencyAndNature(frequency_, nature_)); + // An error check is necessary here to detect allocation failure, but it can + // be folded into a future error check. + gl_internal::UnnecessaryErrorCheck(); + + glCopyNamedBufferSubData(other.buffer_, buffer_, /*readOffset=*/0, + /*writeOffset=*/0, other.size_bytes_); + // This error check is necessary because other might be mapped. + gl_internal::ErrorCheck(); + + fprintf(stderr, "BUFFER COPY\n"); +} + +void Buffer::SetData(const void* data, int size_bytes, + AccessFrequency frequency, AccessNature nature) { + gl_internal::CheckThreadSafety(); + glNamedBufferData(buffer_, size_bytes, data, + CombineFrequencyAndNature(frequency, nature)); + // This error check is necessary to detect allocation failure. + gl_internal::ErrorCheck(); + size_bytes_ = size_bytes; +} + +} // namespace gl |